Income Taxes - Schedule of Components of Net Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Deferred tax assets, Tax loss carryforwards	$ 1,781	$ 1,554
Deferred tax assets, Employee benefits	297	409
Deferred tax assets, Derivatives and hedging activities	283	345
Deferred tax assets, Loss provisions	174	214
Deferred tax assets, Depreciation	128	128
Deferred tax assets, Interest	127	105
Deferred tax assets, Investment basis differences	75	117
Deferred tax assets, Lease assets	24	26
Deferred tax assets, Tax credit carryforwards	23	26
Deferred tax assets, Deferred income/expense	10	2
Deferred tax assets, Other	36	38
Deferred tax assets, Gross	2,958	2,964
Deferred tax assets, Valuation allowance	(2,333)	(2,062)	$ (2,127)	$ (1,778)
Total	625	902
Deferred tax liabilities, Tax loss carryforwards	0	0
Deferred tax liabilities, Employee benefits	0	0
Deferred tax liabilities, Derivatives and hedging activities	24	0
Deferred tax liabilities, Loss provisions	0	0
Deferred tax liabilities, Depreciation	336	425
Deferred tax liabilities, Interest	2	1
Deferred tax liabilities, Investment basis differences	0	0
Deferred tax liabilities, Lease liabilities	23	22
Deferred tax liabilities, Tax credit carryforwards	0	0
Deferred tax liabilities, Deferred income/expense	153	135
Deferred tax liabilities, Other	0	0
Deferred tax liabilities, Gross	538	583
Deferred tax liabilities, Valuation allowance	0	0
Total	$ 538	$ 583