Debt (Schedule of Accounts Receivable Securitization Facility) (Details) - Accounts Receivable Securitization Facility [Member] - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Borrowings outstanding	[1]	$ 77	$ 77
Secured Debt [Member]
Debt Instrument [Line Items]
Borrowings outstanding		77
Letters of credit issued		29
Available for borrowing		3
Total borrowing base		109
Maximum borrowing base	[2]	120
Outstanding accounts receivable transferred by the Originators to the Transferor		$ 188

[1] The weighted average interest rate was 3.4% and 3.1% as of March 31, 2019 and December 31, 2018, respectively.

[2] Outstanding accounts receivable transferred to the SPE was $188 million.