Restructuring, Impairment, and Related Charges - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring, impairment, and related charges recognized	$ 32	$ 60	$ 190	$ 116
Net restructuring, impairment, and related charges recognized	32	60	190	116
Restructuring Plan - Remote Work Transitioning
Restructuring Cost and Reserve [Line Items]
Net restructuring, impairment, and related charges recognized	15		110
Restructuring Plan - Remote Work Transitioning | Minimum | Restructuring Type, Exit Related Costs, Accelerated Depreciation, Amortization and Asset Impairments
Restructuring Cost and Reserve [Line Items]
Expected total pre-tax charges	180		180
Restructuring Plan - Remote Work Transitioning | Maximum | Restructuring Type, Exit Related Costs, Accelerated Depreciation, Amortization and Asset Impairments
Restructuring Cost and Reserve [Line Items]
Expected total pre-tax charges	280		280
Operating Model and Cost Optimization Programs | International
Restructuring Cost and Reserve [Line Items]
Net restructuring, impairment, and related charges recognized	1	$ 27	7	$ 41
Pre-tax charges recorded to-date	64		64
Operating Model and Cost Optimization Programs | Minimum | International
Restructuring Cost and Reserve [Line Items]
Expected total pre-tax charges	85		85
Operating Model and Cost Optimization Programs | Maximum | International
Restructuring Cost and Reserve [Line Items]
Expected total pre-tax charges	$ 90		$ 90