Retirement Benefits Unamortized Prior Service Credit Rollforward (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Amortization of:
Prior service credit	$ 1	$ 10	$ 55
Tax expense (benefit) related to above items	0	(2)	(14)
Change in unamortized benefit plan costs	1	8	41
Pension Benefits
Amortization of:
Prior service credit	0	9	59
Tax expense (benefit) related to above items	0	(2)	(15)
Change in unamortized benefit plan costs	0	7	44
Medical and Life Benefits
Amortization of:
Prior service credit	1	1	(4)
Tax expense (benefit) related to above items	0	0	1
Change in unamortized benefit plan costs	$ 1	$ 1	$ (3)