Fair Value Measurements (Non-Recurring) (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Financing receivables and loans held for sale [Member]	Jun. 30, 2012 Financing receivables and loans held for sale [Member]	Jun. 30, 2013 Financing receivables and loans held for sale [Member]	Jun. 30, 2012 Financing receivables and loans held for sale [Member]	Jun. 30, 2013 Cost and equity method investments [Member]	Jun. 30, 2012 Cost and equity method investments [Member]	Jun. 30, 2013 Cost and equity method investments [Member]	Jun. 30, 2012 Cost and equity method investments [Member]	Jun. 30, 2013 Long Lived Assets, Including Real Estate [Member]	Jun. 30, 2012 Long Lived Assets, Including Real Estate [Member]	Jun. 30, 2013 Long Lived Assets, Including Real Estate [Member]	Jun. 30, 2012 Long Lived Assets, Including Real Estate [Member]	Jun. 30, 2013 Total [Member]	Jun. 30, 2012 Total [Member]	Jun. 30, 2013 Total [Member]	Jun. 30, 2012 Total [Member]	Jun. 30, 2013 Fair Value, Inputs, Level 2 [Member] Financing receivables and loans held for sale [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] Financing receivables and loans held for sale [Member]	Jun. 30, 2013 Fair Value, Inputs, Level 2 [Member] Cost and equity method investments [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] Cost and equity method investments [Member]	Jun. 30, 2013 Fair Value, Inputs, Level 2 [Member] Long Lived Assets, Including Real Estate [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] Long Lived Assets, Including Real Estate [Member]	Jun. 30, 2013 Fair Value, Inputs, Level 2 [Member] Total [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 2 [Member] Total [Member]	Jun. 30, 2013 Fair Value, Inputs, Level 3 [Member] Financing receivables and loans held for sale [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Financing receivables and loans held for sale [Member]	Jun. 30, 2013 Fair Value, Inputs, Level 3 [Member] Cost and equity method investments [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Cost and equity method investments [Member]	Jun. 30, 2013 Fair Value, Inputs, Level 3 [Member] Long Lived Assets, Including Real Estate [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Long Lived Assets, Including Real Estate [Member]	Jun. 30, 2013 Fair Value, Inputs, Level 3 [Member] Total [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Total [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value assets measured on non recurring basis	$ 1,611	$ 2,412																	$ 260	$ 366	$ 13	$ 8	$ 908	$ 702	$ 1,181	$ 1,076	$ 2,658	$ 4,094	$ 778	$ 313	$ 2,284	$ 2,182	$ 5,720	$ 6,589
Adjustments To Assets Measured At Fair Value On Non Recurring Basis			$ (102)	$ (105)	$ (212)	$ (211)	$ (157)	$ (38)	$ (220)	$ (58)	$ (253)	$ (106)	$ (593)	$ (245)	$ (512)	$ (249)	$ (1,025)	$ (514)