Long-Term Debt and Credit Facilities-Future Payments (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013
Long-term Debt, Fiscal Year Maturity [Abstract]
2014	$ 785	[1]
2015	565	[1]
2016	1,493	[1]
2017	2,219	[1]
2018	246	[1]
2019 and thereafter	15,736	[1]
Total long-term debt	$ 21,044	[1]

[1] Actual principal paid in all years may differ due to the possible future refinancing of outstanding debt or the issuance of new debt.