Retirement Benefits Unamortized Prior Service Credit Rollforward (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Amortization of:
Prior service credit	$ 10	$ 55	$ 62
Tax expense (benefit) related to above items	(2)	(14)	(15)
Change in unamortized benefit plan costs	8	41	47
Pension Benefits
Amortization of:
Prior service credit	9	59	59
Tax expense (benefit) related to above items	(2)	(15)	(14)
Change in unamortized benefit plan costs	7	44	45
Medical and Life Benefits
Amortization of:
Prior service credit	1	(4)	3
Tax expense (benefit) related to above items	0	1	(1)
Change in unamortized benefit plan costs	$ 1	$ (3)	$ 2