Financial Instruments Recorded at Carrying Amount (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt	$ 2,289		$ 2,085
Project Debt	228		236
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts Receivable, Fair Value Disclosure	286	[1]	289	[1]
Long-term Debt	2,289		2,085
Project Debt	228		236
Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts Receivable, Fair Value Disclosure	286	[1]	289	[1]
Long-term Debt	2,349		2,092
Project Debt	$ 240		$ 248

[1] Includes $23 million and $24 million of noncurrent receivables in other noncurrent assets in the condensed consolidated balance sheets as of March 31, 2014 and December 31, 2013, respectively.