Comprehensive (Loss) Income (Narrative) (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		9 Months Ended	12 Months Ended
	Mar. 27, 2019	Nov. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2019	Mar. 31, 2020	Nov. 05, 2019	Dec. 31, 2018
Interest rate swap contracts
Derivative [Line Items]
Derivative Notional Amount Agreement Terminated	$ 441	$ 171	$ 38	$ 441	$ 650
Derivative, Notional Amount	650			650	550	$ 550	$ 550	$ 550	$ 650
Amount Received From Terminated Interest Rate Swap	11	$ 0	$ 1	11		12
Derivative, Fair Value, Net				$ 11	$ 12	$ 12
Interest rate swap, remaining unamortized amount							$ 7
Interest Rate Swap Contracts II [Member]
Derivative [Line Items]
Derivative Notional Amount Agreement Terminated	209
Derivative, Notional Amount	650
Amount Received From Terminated Interest Rate Swap	$ 1