Long-Term Debt and Credit Facilities (Details 4) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Long-term Debt, Fiscal Year Maturity [Abstract]
2015	$ 550	[1]
2016	1,494	[1]
2017	1,497	[1]
2018	248	[1]
2019	1,474	[1]
2020 and thereafter	15,519	[1]
Total long-term debt	$ 20,782	[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.