Debt (Schedule of Accounts Receivable Securitization Facility)(Details) - Accounts Receivable Securitization Facility [Member] - USD ($) $ in Millions		3 Months Ended	6 Months Ended
		Jun. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Borrowings outstanding	[1]	$ 71	$ 71	$ 0
Secured Debt [Member]
Debt Instrument [Line Items]
Borrowings outstanding	[2]	71	71
Letters of credit issued		39	39
Available for borrowing		10	10
Total borrowing base		120	120
Maximum borrowing base	[3]	120	120
Proceeds from Issuance of Debt		75
Repayments of Lines of Credit		$ 4
Outstanding accounts receivable transferred by the Originators to the Transferor			$ 174

[1] The weighted average interest rate was 1.8% as of June 30, 2017.

[2] The Company borrowed $75 million and repaid $4 million under its Accounts Receivable Securitization Facility during the three months ended June 30, 2017.

[3] Outstanding accounts receivable transferred to the SPE was $174 million.