Strategic Initiatives (Details) - 2-year Restructuring Plan [Member] - USD ($) $ in Millions	3 Months Ended		24 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 18	$ 109
Restructuring charges recorded to date	298
Forecast [Member]
Restructuring Cost and Reserve [Line Items]
Expected period for completion of restructuring plan			2 years
Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	520			$ 520
Expected restructuring charges, after-tax				390
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	$ 590			590
Expected restructuring charges, after-tax				$ 450