Long-Term Debt Long Term Debt Maturties Schedule (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Debt Disclosure [Abstract]
2013	$ 7,868	[1]
2014	3,846
2015	5,810
2016	5,178
2017	1,659
Thereafter	4,065
Total	$ 28,426		$ 39,790
Weighted average interest rate on debt maturing in next twelve months	4.82%

[1] Weighted average interest rate on long-term debt maturing in 2013 is 4.82 percent.