Fair Value Measurements (Non-Recurring) (Details) - Non-recurring [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Adjustment to assets measured at fair value on non recurring basis	$ (410)	$ (373)	$ (4,064)	$ (721)
Financing receivables and loans held for sale [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Adjustment to assets measured at fair value on non recurring basis	(46)	(31)	(2,199)	(135)
Cost and equity method investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Adjustment to assets measured at fair value on non recurring basis	(279)	(80)	(1,741)	(274)
Long Lived Assets, Including Real Estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Adjustment to assets measured at fair value on non recurring basis	(85)	$ (262)	(125)	$ (312)
Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets Fair Value Disclosure	4		4		$ 103
Fair Value, Inputs, Level 2 | Financing receivables and loans held for sale [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets Fair Value Disclosure	0		0		1
Fair Value, Inputs, Level 2 | Cost and equity method investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets Fair Value Disclosure	1		1		0
Fair Value, Inputs, Level 2 | Long Lived Assets, Including Real Estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets Fair Value Disclosure	3		3		102
Fair Value, Inputs, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets Fair Value Disclosure	20,785		20,785		1,636
Fair Value, Inputs, Level 3 | Financing receivables and loans held for sale [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets Fair Value Disclosure	18,152		18,152		584
Fair Value, Inputs, Level 3 | Cost and equity method investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets Fair Value Disclosure	2,336		2,336		334
Fair Value, Inputs, Level 3 | Long Lived Assets, Including Real Estate [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets Fair Value Disclosure	$ 296		$ 296		$ 718