Redeemable Noncontrolling Interests and Noncontrolling Interests - Schedule of Changes in Noncontrolling Interests and Redeemable Noncontrolling Interest (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance	$ 217
Net income attributable to noncontrolling interests	199	$ 220	$ 221
Other comprehensive income (loss)	(53)	3
Ending balance	196	217
Redeemable Noncontrolling Interest, Beginning balance	1,402
Payments to noncontrolling interests	(177)	(154)	(184)
Exercises of put right	3
Redeemable Noncontrolling Interest, Ending balance	1,271	1,402
Noncontrolling interests
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance	217	193	253
Net income attributable to noncontrolling interests	156	178	176
Other comprehensive income (loss)	0	0	0
Other	0	0	(52)
Ending balance	196	217	193
Payments to noncontrolling interests	(177)	(154)	(184)
Other	0	0	(52)
Redeemable Noncontrolling Interests
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Other comprehensive income (loss)	(79)	3	(66)
Other	(3)	6	0
Redeemable Noncontrolling Interest, Beginning balance	1,402	1,393	1,459
Net income attributable to noncontrolling interests	43	42	45
Reclassification of recurring compensation to other accrued liabilities	(43)	(42)	(45)
Payments to noncontrolling interests	0	0	0
Exercises of put right	(49)
Other	(3)	6	0
Redeemable Noncontrolling Interest, Ending balance	$ 1,271	$ 1,402	$ 1,393