Employee Retirement Benefits - Net Periodic Income Cost Recognizedf for OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Reclassification from accumulated other comprehensive income (loss) to net income	$ 5	$ 2	$ (3)
Tax effects on components of net periodic income (cost) recognized in OCI [Abstract]
Reclassification from accumulated other comprehensive income (loss) to net income, tax expense (benefit)	(1)	(1)	(1)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net gains (losses)	95	42	(36)
Reclassification from accumulated other comprehensive income (loss) to net income	6	5	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent	101	47	(36)
Tax effects on components of net periodic income (cost) recognized in OCI [Abstract]
Net gains (losses)	29	13	$ (10)
Reclassification from accumulated other comprehensive income (loss) to net income, tax expense (benefit)	$ 2	$ 1