Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Increase (Decrease) in Stockholders' Equity
Balance as of beginning of period	$ (428)	$ (133)	$ (381)	$ (238)
Other comprehensive (loss) income before reclassifications	144	(191)	9	(38)
Amounts reclassified from accumulated other comprehensive loss, net	(21)	(58)	67	(106)
Net current-period other comprehensive income (loss)	123	(249)	76	(144)
Balance as of end of period	(305)	(382)	(305)	(382)
Currency Translation
Increase (Decrease) in Stockholders' Equity
Balance as of beginning of period	(362)	(309)	(340)	(293)
Other comprehensive (loss) income before reclassifications	138	(63)	116	(79)
Amounts reclassified from accumulated other comprehensive loss, net	0	0	0	0
Net current-period other comprehensive income (loss)	138	(63)	116	(79)
Balance as of end of period	(224)	(372)	(224)	(372)
Cash Flow Hedges
Increase (Decrease) in Stockholders' Equity
Balance as of beginning of period	(85)	119	(62)	(5)
Other comprehensive (loss) income before reclassifications	9	(129)	(104)	42
Amounts reclassified from accumulated other comprehensive loss, net	(21)	(55)	69	(102)
Net current-period other comprehensive income (loss)	(12)	(184)	(35)	(60)
Balance as of end of period	(97)	(65)	(97)	(65)
Postretirement Benefit Plans
Increase (Decrease) in Stockholders' Equity
Balance as of beginning of period	19	57	21	60
Other comprehensive (loss) income before reclassifications	(3)	1	(3)	(1)
Amounts reclassified from accumulated other comprehensive loss, net	0	(3)	(2)	(4)
Net current-period other comprehensive income (loss)	(3)	(2)	(5)	(5)
Balance as of end of period	$ 16	$ 55	$ 16	$ 55