Strategic Initiatives (Details) - Restructuring Plan [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended		24 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 47	$ 84	$ 183	$ 244
Restructuring charges recorded to date	463		463
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	900		900			$ 520
Expected restructuring charges, after-tax						390
Additional expected restructuring charges pre-tax	380		380
Additional expected restructuring charges, after-tax	290		290
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges, pre-tax	1,000		1,000			590
Expected restructuring charges, after-tax						$ 450
Additional expected restructuring charges pre-tax	410		410
Additional expected restructuring charges, after-tax	$ 310		$ 310