Debt (Debt) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Debt Instrument [Line Items]
Long-term Debt	$ 10,750		$ 10,425
Debt, Current	115		104
Debt, net of current portion	10,635		10,321
Corporate Debt Securities [Member]
Debt Instrument [Line Items]
Long-term Debt	5,303	[1]	5,892	[1]
Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Long-term Debt	1,789	[1]	1,691	[1]
Loans Payable [Member]
Debt Instrument [Line Items]
Long-term Debt	2,463	[1]	1,646	[1]
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt	978		972
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 217		$ 224

[1] During the fourth quarter of 2012, we redeemed 10% of the aggregate principal amount of our First Lien Notes and repaid project debt with proceeds received from the issuance of our 2019 First Lien Term Loan.