Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Cash and Cash Equivalents At Carrying Value Attributable to VIE	$ 151	$ 109
Allowance for Doubtful Accounts Receivable, Current	2	6
Restricted Cash And Cash Equivalents At Carrying Value Attributable To Vie	63	53
Property Plant And Equipment Net Attributable To Vie	4,226	4,192
Restricted Cash And Cash Equivalents Noncurrent Attributable To Vie	56	59
Debt, current portion attributable to VIE	81	39
Long Term Debt Noncurrent Attributable To Vie	$ 2,682	$ 2,660
Preferred Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Preferred Stock, Shares Authorized	100,000,000	100,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Common Stock, Shares Authorized	1,400,000,000	1,400,000,000
Common Stock, Shares, Issued	494,762,280	492,495,100
Common Stock, Shares, Outstanding	455,000,065	457,048,970
Treasury Stock, Shares	39,762,215	35,446,130