Fair Value Measurements (Significant Unobservable Input) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement Recurring Basis, Asset Value	2,676	2,598
Fair Value, Measurements, Recurring
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement Recurring Basis, Asset Value	42	82
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value measurments - nonrecurring	3,741	96
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement Recurring Basis, Asset Value	4,631	12,092	11,592	11,261
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Domestic Corporate Debt Securities [Member] | Income Approach [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement Recurring Basis, Asset Value	1,015	980
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Domestic Corporate Debt Securities [Member] | Income Approach, Busines Enterprise Value [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement Recurring Basis, Asset Value		980
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Domestic Corporate Debt Securities [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Lower Limit
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	170.00%	150.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Domestic Corporate Debt Securities [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Maximum [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	1320.00%	1480.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Domestic Corporate Debt Securities [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Weighted Average [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	670.00%	660.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Asset-backed Securities [Member] | Income Approach [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement Recurring Basis, Asset Value	99	7,554
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Asset-backed Securities [Member] | Income Approach, Busines Enterprise Value [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement Recurring Basis, Asset Value		7,554
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Asset-backed Securities [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Lower Limit
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	530.00%	220.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Asset-backed Securities [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Maximum [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	900.00%	1240.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Asset-backed Securities [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Weighted Average [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	560.00%	500.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Foreign Corporate Debt Securities [Member] | Income Approach [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement Recurring Basis, Asset Value	333	388
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Foreign Corporate Debt Securities [Member] | Income Approach, Busines Enterprise Value [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement Recurring Basis, Asset Value		388
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Foreign Corporate Debt Securities [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Lower Limit
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	20.00%	40.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Foreign Corporate Debt Securities [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Maximum [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	1400.00%	1400.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Foreign Corporate Debt Securities [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Weighted Average [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	560.00%	570.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | State And Municipal Debt Securities [Member] | Income Approach [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement Recurring Basis, Asset Value	456	481
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | State And Municipal Debt Securities [Member] | Income Approach, Busines Enterprise Value [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair Value, Measurement Recurring Basis, Asset Value		481
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | State And Municipal Debt Securities [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Lower Limit
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	280.00%	190.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | State And Municipal Debt Securities [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Maximum [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	630.00%	590.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | State And Municipal Debt Securities [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Weighted Average [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	480.00%	280.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value measurments - nonrecurring	40,043	82
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Lower Limit
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	100.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Maximum [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	3000.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Financing receivables and loans held for sale [Member] | Income Approach [Member] | Weighted Average [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate	850.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Financing receivables and loans held for sale [Member] | Business Enterprise Value Valuation Technique [Member] | Lower Limit
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
EBITDA Multiple		4.3
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Financing receivables and loans held for sale [Member] | Business Enterprise Value Valuation Technique [Member] | Maximum [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
EBITDA Multiple		6.5
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Financing receivables and loans held for sale [Member] | Business Enterprise Value Valuation Technique [Member] | Weighted Average [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
EBITDA Multiple		6.2
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Financing receivables and loans held for sale [Member] | Income Approach, Busines Enterprise Value [Member] | Lower Limit
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
EBITDA Multiple	0
Capitalization Rate	1.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Financing receivables and loans held for sale [Member] | Income Approach, Busines Enterprise Value [Member] | Maximum [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
EBITDA Multiple	0
Capitalization Rate	30.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Financing receivables and loans held for sale [Member] | Income Approach, Busines Enterprise Value [Member] | Weighted Average [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
EBITDA Multiple	0
Capitalization Rate	8.50%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Market Comparables [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value measurments - nonrecurring	1,928
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Market Comparables [Member] | Lower Limit
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Revenue multiple	0.4
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Market Comparables [Member] | Maximum [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Revenue multiple	1
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Market Comparables [Member] | Weighted Average [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Revenue multiple	0.6
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Income Approach, Business Enterprise, Market comparables [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value measurments - nonrecurring		343
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Income Approach, Business Enterprise, Market comparables [Member] | Lower Limit
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
EBITDA Multiple		1.8
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Income Approach, Business Enterprise, Market comparables [Member] | Maximum [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
EBITDA Multiple		10.5
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Income Approach, Business Enterprise, Market comparables [Member] | Weighted Average [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
EBITDA Multiple		7
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Income Approach, Market Comparables [Member] | Lower Limit
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate		8.00%
Capitalization Rate		1.80%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Income Approach, Market Comparables [Member] | Maximum [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate		10.00%
Capitalization Rate		10.50%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Income Approach, Market Comparables [Member] | Weighted Average [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate		9.40%
Capitalization Rate		7.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Income Approach, Busines Enterprise Value [Member] | Lower Limit
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
EBITDA Multiple	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Income Approach, Busines Enterprise Value [Member] | Maximum [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
EBITDA Multiple	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Cost and equity method investments [Member] | Income Approach, Busines Enterprise Value [Member] | Weighted Average [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
EBITDA Multiple	0
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Long Lived Assets, Including Real Estate [Member] | Income Approach [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Fair value measurments - nonrecurring	381	666
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Long Lived Assets, Including Real Estate [Member] | Income Approach [Member] | Lower Limit
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate		200.00%
Capitalization Rate	450.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Long Lived Assets, Including Real Estate [Member] | Income Approach [Member] | Maximum [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate		1900.00%
Capitalization Rate	1540.00%
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Nonrecurring [Member] | Long Lived Assets, Including Real Estate [Member] | Income Approach [Member] | Weighted Average [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Discount Rate		680.00%
Capitalization Rate	760.00%