Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2021		Jun. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (50)	[1]	$ (50)
Other comprehensive income (loss) before reclassifications	4		3
Amounts reclassified from accumulated other comprehensive income (loss)	11		(5)
Total other comprehensive income (loss), net of tax	15		(2)
Ending balance	(35)		(52)
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	0		(4)
Other comprehensive income (loss) before reclassifications	0		11
Amounts reclassified from accumulated other comprehensive income (loss)	0		0
Total other comprehensive income (loss), net of tax	0		11
Ending balance	0		7
Unrealized Gains (Losses) on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(29)		39
Other comprehensive income (loss) before reclassifications	(5)		(32)
Amounts reclassified from accumulated other comprehensive income (loss)	11		(5)
Total other comprehensive income (loss), net of tax	6		(37)
Ending balance	(23)		2
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(21)		(85)
Other comprehensive income (loss) before reclassifications	9		24
Amounts reclassified from accumulated other comprehensive income (loss)	0		0
Total other comprehensive income (loss), net of tax	9		24
Ending balance	$ (12)		$ (61)

[1] Derived from audited Consolidated Financial Statements.