Redeemable Noncontrolling Interests and Noncontrolling Interests - Schedule of Changes in Redeemable Noncontrolling Interests and Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Noncontrolling Interests
Beginning balance			$ 217
Net income attributable to noncontrolling interests	$ 50	$ 53	100	$ 107
Other comprehensive loss	(125)	(18)	(64)	(12)
Payments to noncontrolling interests	(50)	(37)	(93)	(76)
Ending balance	200		200
Redeemable Noncontrolling Interests
Beginning balance			1,402
Other comprehensive loss	(125)	(18)	(64)	(12)
Payments to noncontrolling interests	(50)	(37)	(93)	(76)
Ending balance	1,265		1,265
Noncontrolling Interests
Noncontrolling Interests
Beginning balance	207	194	217	193
Net income attributable to noncontrolling interests	40	42	79	85
Other comprehensive loss	0	0	0	0
Payments to noncontrolling interests	(50)	(37)	(93)	(76)
Other	3	11	(3)	8
Ending balance	200	210	200	210
Redeemable Noncontrolling Interests
Other comprehensive loss	0	0	0	0
Payments to noncontrolling interests	(50)	(37)	(93)	(76)
Other	3	11	(3)	8
Redeemable Noncontrolling Interest
Noncontrolling Interests
Other comprehensive loss	(151)	(18)	(90)	(12)
Payments to noncontrolling interests	0	0	0	0
Other	2	3	2	3
Redeemable Noncontrolling Interests
Beginning balance	1,414	1,399	1,402	1,393
Net income attributable to noncontrolling interests	10	11	21	22
Other comprehensive loss	(151)	(18)	(90)	(12)
Reclassification of recurring compensation to other accrued liabilities	(10)	(11)	(21)	(22)
Payments to noncontrolling interests	0	0	0	0
Exercises of Put Right			(49)
Other	2	3	2	3
Ending balance	$ 1,265	$ 1,384	$ 1,265	$ 1,384