Stockholders' Equity Tax Benefit (Expense) on Net Activity (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Tax Benefit (Expense)	$ 36	$ 4	$ 103	$ 3
Pension Plan
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Tax Benefit (Expense)	(3)	0	(8)	(3)
Other Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Tax Benefit (Expense)	51	0	148	0
Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Tax Benefit (Expense)	$ (12)	$ 4	$ (37)	$ 6