Employee Retirement Benefits - Net Periodic Income Cost Regulatory Assets (Details) - Pension Benefits [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost Recognized In Regulatory Assets Liabilities	$ (1)	$ 1
Unrecognized gains	(226)	(89)
Amortization of prior service benefit	0	1
Amortization Of Unrecognized Losses Recognized In Regulatory Assets Liabilities	(16)	(12)
Total	$ (243)	$ (99)