Debt (Schedule of Balances Available for Borrowings)(Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016		Dec. 31, 2015	Sep. 30, 2014
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Borrowings outstanding	[2]	$ 0	[1]	$ 350
Letters of credit issued		0
Available for borrowing		900
Maximum borrowing base		900			$ 900
Proceeds from lines of credit		245
Repayments of lines of credit		595
Accounts Receivable Securitization Facility [Member]
Debt Instrument [Line Items]
Borrowings outstanding	[4]	0	[3]	$ 55
Letters of credit issued		52
Available for borrowing		61
Total borrowing base		113
Maximum borrowing base	[5]	120
Repayments of lines of credit		55
Outstanding accounts receivable transferred by the Originators to the Transferor		$ 136

[1] The Company borrowed $245 million and repaid $595 million during the three months ended March 31, 2016.

[2] The weighted average interest rate was 1.8% as of December 31, 2015.

[3] The Company repaid $55 million during the three months ended March 31, 2016.

[4] The weighted average interest rate was 0.8% as of December 31, 2015.

[5] Outstanding accounts receivable transferred by the Originators to the Transferor was $136 million.