Exit and Other Related Liabilities (Narrative) (Details) - USD ($) $ in Millions		3 Months Ended		18 Months Ended
	Oct. 06, 2020	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022
Restructuring Cost and Reserve [Line Items]
Acquisition-related exit costs incurred			$ 43	$ 306
Acquisition-related Costs
Restructuring Cost and Reserve [Line Items]
Acquisition-related exit costs incurred		$ 12	$ 43
Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Client conversion period	30 months
Expected integration exit and other related costs		$ 650		650
Expected period of remaining costs to be incurred		18 months
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Client conversion period	36 months
Expected integration exit and other related costs		$ 1,000		$ 1,000
Expected period of remaining costs to be incurred		30 months