Debt Debt (Accounts Receivable Securitization Facility) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016		Jul. 08, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Cash Flows Between Transferor and Transferee, Proceeds from New Transfers		$ 148
Accounts Receivable Securitization Facility [Member]
Debt Instrument [Line Items]
Line of Credit, Current	[2]	0	[1]		$ 55
Letters of credit issued		52
Available for borrowing		52
Line of Credit Facility, Current Borrowing Capacity		104
Line of Credit Facility, Maximum Borrowing Capacity		120	[3]	$ 120
Repayments of Lines of Credit		$ 55

[1] The Company repaid $55 million during the year ended December 31, 2016.

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

[3] Outstanding accounts receivable transferred to the SPE was $148 million.