Condensed Consolidated Statements of Stockholders' Equity Statement - USD ($) shares in Thousands, $ in Millions	Total		Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (loss)
Beginning balance (in shares) at Mar. 31, 2020			288,413
Beginning balance at Mar. 31, 2020	$ 7,461		$ 3	$ 0	$ 7,508	$ (50)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss) before reclassifications	3
Amounts reclassified from accumulated other comprehensive income (loss)	(5)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	363				365	(2)
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	102			102
Stock Issued During Period, Shares, New Issues			1,088
Stock Issued During Period, Value, New Issues	(66)			(66)
Stock Repurchased and Retired During Period, Shares			(747)
Stock Repurchased and Retired During Period, Value	(78)			(36)	(42)
Ending balance (in shares) at Jun. 30, 2020			288,754
Ending balance at Jun. 30, 2020	$ 7,782		$ 3	0	7,831	(52)
Beginning balance (in shares) at Mar. 31, 2021	286,000		286,465
Beginning balance at Mar. 31, 2021	$ 7,840	[1]	$ 3	0	7,887	(50)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss) before reclassifications	4
Amounts reclassified from accumulated other comprehensive income (loss)	11
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	219				204	15
APIC, Share-based Payment Arrangement, Increase for Cost Recognition	125			125
Stock Issued During Period, Value, Acquisitions	23			23
Stock Issued During Period, Shares, New Issues			1,209
Stock Issued During Period, Value, New Issues	(105)			(105)
Stock Repurchased and Retired During Period, Shares			(2,292)
Stock Repurchased and Retired During Period, Value	(325)			(43)	(282)
Cash dividends declared ($0.17 per common share)	$ (49)				(49)
Common Stock, Dividends, Per Share, Declared	$ 0.17
Ending balance (in shares) at Jun. 30, 2021	285,000		285,382
Ending balance at Jun. 30, 2021	$ 7,728		$ 3	$ 0	$ 7,760	$ (35)

[1] Derived from audited Consolidated Financial Statements.