Income Taxes - Schedule of Components of Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Deferred tax assets, depreciation	$ 8	$ 21
Deferred tax assets, employee benefits	300	364
Deferred tax assets, loss provisions	20	24
Deferred tax assets, deferred income	50	41
Deferred tax assets, interest	105	3
Deferred tax assets, tax loss carryforwards	3,226	3,267
Deferred tax assets, tax credit carryforwards	358	378
Deferred tax assets, other	10	7
Deferred tax assets, gross	4,077	4,105
Valuation allowance	(2,279)	(2,307)	$ (2,121)	$ (2,357)
Deferred tax assets, net	1,798	1,798
Deferred tax liabilities, depreciation	538	506
Deferred tax liabilities, employee benefits	3	0
Deferred tax liabilities, loss provisions	1	1
Deferred tax liabilities, deferred expense	1,098	1,033
Deferred tax liabilities, interest	0	0
Deferred tax liabilities, tax loss carryforwards	0	0
Deferred tax liabilities, tax credit carryforwards	0	0
Deferred tax liabilities, other	7	13
Deferred tax liabilities, gross	$ 1,647	$ 1,553