Schedule I Condensed Financial Information Parent Company Balance Sheets Parenthetical (Details) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Financial Statements [Line Items]
Allowance for Doubtful Accounts Receivable, Current	$ 99	$ 99
Accumulated depreciation	(9,158)	(8,991)
Preferred Stock, Shares Authorized	50,000,000	50,000,000
Preferred Stock, Shares Outstanding	10,000,000	10,000,000
Common Stock, Shares Authorized	450,000,000	450,000,000
Common Stock, Shares, Outstanding	248,000,000	245,000,000
Parent Company
Condensed Financial Statements [Line Items]
Allowance for Doubtful Accounts Receivable, Current	21	22
Accumulated depreciation	$ (4,032)	$ (4,084)
Preferred Stock, Shares Authorized	50,000,000
Preferred Stock, Shares Outstanding	10,000,000	10,000,000
Common Stock, Shares Authorized	450,000,000
Common Stock, Shares, Outstanding	248,000,000	245,000,000
Common Stock, Shares, Issued	0	0	0