Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Income Tax Disclosure [Line Items]
Effective income tax rate	3.70%	33.40%		17.60%	28.60%
Tax Adjustments, Settlements, and Unusual Provisions			$ 145
Unrecognized Tax Benefits	1,420			1,420		1,141
Tax Basis Restoration [Member]
Income Tax Disclosure [Line Items]
Tax Adjustments, Settlements, and Unusual Provisions	265
2007-2008 Federal Tax Audit Settlement [Member]
Income Tax Disclosure [Line Items]
Tax Adjustments, Settlements, and Unusual Provisions	116
2009-2010 Federal Tax Audit Settlement [Member]
Income Tax Disclosure [Line Items]
Tax Adjustments, Settlements, and Unusual Provisions	$ 143