Fair Value Level 4 (Details) - Fair Value Hierarchy - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative Liabilities	$ 1
Unrealized Loss on Foreign Currency Derivatives, before Tax	1
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	2	$ 0	$ 0	$ 0
Gain (Loss) on Fair Value Hedges Recognized in Earnings	(1)
Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative notional amount, Interest Rate Swap	$ 300
Interest Rate Cap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative, Notional Amount					$ 375