Derivative Instruments - Narrative (Details) - USD ($)	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019
Derivative [Line Items]
Cash flow hedge adjustments, net of tax	$ (18,000,000)	$ (1,000,000)
Interest Rate Swap
Derivative [Line Items]
Pre-tax impact of gain (loss) on derivatives	(24,000,000)	(1,000,000)
Cash flow hedge adjustments, net of tax	(18,000,000)	(1,000,000)
Interest Rate Swap | Interest Expense
Derivative [Line Items]
Gain on cash flow hedge ineffectiveness		$ (5,000,000)
Derivatives Designated for Hedge Accounting | Interest Rate Swap
Derivative [Line Items]
Foreign currency cash flow hedge gain to be reclassified during next 12 months	15,000,000
Derivative liability, fair value	50,000,000		$ 26,000,000
Derivatives Designated for Hedge Accounting | Interest Rate Swap | Other Current Liabilities
Derivative [Line Items]
Derivative liability, fair value	13,000,000		4,000,000
Derivatives Designated for Hedge Accounting | Interest Rate Swap | Other Liabilities
Derivative [Line Items]
Derivative liability, fair value	37,000,000		$ 22,000,000
Derivatives Designated for Hedge Accounting | Cash Flow Hedging | Interest Rate Swap
Derivative [Line Items]
Derivative notional amount	$ 1,600,000,000