In this answer, I’ve cited the IATA guidelines, which most airlines will likely follow (though deviations are possible).

In summary, you should be fine if your computer’s unremovable battery is up to 160 Wh. Current MacBook Pros (as of 2016) should be under 100 Wh.

The Lithium Battery Guidance Document for 2015 states (emphasis added):

Passenger Provisions [p. 12]

2.3.4.7 Lithium Battery-Powered Electronic Devices

Lithium battery-powered electronic devices are permitted in checked and carry-on baggage with the approval of the operator as follows:

[…]
(b) portable electronic devices (such as cameras, lap-top computers, camcorders) containing lithium ion batteries as follows:
  1. lithium ion batteries with a watt-hour rating exceeding 100 Wh, but not exceeding 160 Wh;
  2. batteries must be of a type that meets the requirements of the UN Manual of Tests and Criteria, Part III, subsection 38.3.

2.3.5.9 Portable Electronic Devices (including medical devices) containing Batteries

2.3.5.9.1 Portable electronic devices (including medical devices) (such as watches, calculating machines, cameras, cellular phones, lap-top computers, camcorders, etc.) containing batteries when carried by passengers or crew for personal use, which should be carried in carry-on baggage. Spare batteries must be individually protected to prevent short circuits by placement in the original retail packaging or by otherwise insulating terminals, e.g. by taping over exposed terminals or placing each battery in a separate plastic bag or protective pouch, and carried in carry-on baggage only. In addition, lithium batteries are subject to the following conditions:

(a) each installed or spare battery must not exceed:
  1. for lithium metal or lithium alloy batteries, a lithium content of not more than 2 g; or
  2. for lithium ion batteries, a watt-hour rating of not more than 100 Wh.
[…]

There is also provision, with the approval of the airline, for larger lithium ion batteries with a watt-hour rating in excess of 100 Wh, but not more than 160 Wh in equipment and no more than two spare lithium ion batteries as set out in subparagraph 2.3.3.2 as follows:

2.3.3.2 Lithium ion batteries exceeding a watt-hour rating of 100 Wh but not exceeding 160 Wh may be carried as spare batteries in carry-on baggage, or in equipment in either checked or carry-on baggage. Batteries must be of a type that meets the requirements of the UN Manual of Tests and Criteria, Part III, subsection 38.3. No more than two individually protected spare batteries per person may be carried.

According to the United States FAA, lithium-ion batteries are allowed in checked baggage so long as they are in a consumer electronic device and they are not too large.

The FAA has separate regulations about "portable electronic devices, containing batteries" and "lithium ion and lithium metal batteries, spare (uninstalled)". For the former:

Most consumer personal electronic devices containing batteries are allowed in carry-on and checked baggage, including but not limited to cell phones, smart phones, PDAs, electronic games, tablets, laptop computers, cameras, camcorders, watches, calculators, etc. This covers typical dry cell batteries including lithium metal and lithium ion batteries for consumer electronics (AA, AAA, C, D, button cell, camera batteries, laptop batteries, etc.)

…

Quantity limits: None except that larger lithium ion batteries and spare nonspillable wet (gel cell, absorbed electrolyte) batteries are limited to two per person. For size restrictions on lithium metal, lithium ion, and nonspillable wet (gel cell, absorbed electrolyte) batteries, see separate "Spare batteries" entries in this table.

For the latter:

Spare (uninstalled) lithium ion and lithium metal batteries must be carried in carry-on baggage only. When a carry-on bag is checked at the gate or at planeside, all spare lithium batteries must be removed from the bag and kept with the passenger in the aircraft cabin. The battery terminals must be protected from short circuit.

…

Size limits: Lithium metal (non-rechargeable) batteries are limited to 2 grams of lithium per battery. Lithium ion (rechargeable) batteries are limited to a rating of 100 watt hours (Wh) per battery. These limits allow for nearly all types of lithium batteries used by the average person in their electronic devices. With airline approval, passengers may also carry up to two spare larger lithium ion batteries (101-160 watt hours). This size covers the larger after-market extended-life laptop computer batteries and some larger batteries used in professional audio/visual equipment.

Quantity limits: None for most batteries – but batteries must be for use by the passenger. Batteries carried for further sale or distribution (vendor samples, etc.) are prohibited. There is a limit of two spare batteries per person for the larger lithium ion batteries described above (101-160 watt hours per battery).

For reference:

1. The 15″ MacBook Pro carries a 99.5 watt hour battery.
2. The 13″ MacBook Pro carries a 74.9 watt hour battery.
3. The MacBook Air 13″ carries a 54 watt hour battery.
4. The MacBook carries a 41.4 watt hour battery.
5. The 12″ iPad Pro carries a 38.5 watt hour battery.
6. The MacBook Air 11″ carries a 38 watt hour battery.
7. The 9.7″ iPad Pro carries a 27.5 watt hour battery.
8. The iPad Air 2 carries a 27.3 watt hour battery.
9. The iPad Mini 4 carries a 19.1 watt hour battery.

You are absolutely allowed to put them in checked luggage. The difference arises on the watt-hour rating of the battery. Anything that is 160 watt-hour or more (these are usually found in mobility scooters, electric wheels chairs, etc.) is not allowed in baggage and must be carried as cargo.

Non-rechargeable batteries (such as those you buy at the counter in your favorite supermarket, usually have sizes like AAA, AA, A, etc.) usually have restrictions. Check with your airline. Some allow all the way up to “D”, others, like Cathay restrict those above a size “C”.

Battery types are allowed both in carry-on and in luggage hold; with the following conditions:

1. Spare batteries or naked batteries (those removed from the device) are not allowed to be checked-in and must be carried on.

2. Spares and naked batteries must be carried in its original packaging and/or the terminals are to be covered as to prevent contact.

3. There is a limit (check with your airline, but most limit to 10) to how many devices you can check-in (cargo) that have batteries; and there is a limit of how many spares (batteries) you can carry on with you.

Cathay Pacific’s website, and this pdf from British Airways and this guide from the FAA have some more details for you.

Please make sure you check with your airline before you travel, as there may be further restrictions (usually on quantity) based on your itinerary.