Fair Value Measurements (Non-Recurring Measurement) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Domestic Corporate Debt Securities [Member] Income Approach Valuation Technique [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Domestic Corporate Debt Securities [Member] Income Approach Valuation Technique [Member] Lower Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Domestic Corporate Debt Securities [Member] Income Approach Valuation Technique [Member] Upper Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Asset-backed Securities [Member] Income Approach Valuation Technique [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Asset-backed Securities [Member] Income Approach Valuation Technique [Member] Lower Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Asset-backed Securities [Member] Income Approach Valuation Technique [Member] Upper Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Foreign Corporate Debt Securities [Member] Income Approach Valuation Technique [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Foreign Corporate Debt Securities [Member] Income Approach Valuation Technique [Member] Lower Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Foreign Corporate Debt Securities [Member] Income Approach Valuation Technique [Member] Upper Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Other Items [Member] Income Approach Valuation Technique [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Other Items [Member] Income Approach Valuation Technique [Member] Lower Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member] Other Items [Member] Income Approach Valuation Technique [Member] Upper Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Financing receivables and loans held for sale [Member] Income Approach Valuation Technique [Member] Capitalization Rate Unobservable Inputs [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Financing receivables and loans held for sale [Member] Income Approach Valuation Technique [Member] Capitalization Rate Unobservable Inputs [Member] Lower Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Financing receivables and loans held for sale [Member] Income Approach Valuation Technique [Member] Capitalization Rate Unobservable Inputs [Member] Upper Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Financing receivables and loans held for sale [Member] Business Enterprise Value Valuation Technique [Member] EBITDA Multiple [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Financing receivables and loans held for sale [Member] Business Enterprise Value Valuation Technique [Member] EBITDA Multiple [Member] Lower Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Financing receivables and loans held for sale [Member] Business Enterprise Value Valuation Technique [Member] EBITDA Multiple [Member] Upper Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Cost and equity method investments [Member] Income Approach Valuation Technique [Member] Capitalization Rate Unobservable Inputs [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Cost and equity method investments [Member] Income Approach Valuation Technique [Member] Capitalization Rate Unobservable Inputs [Member] Lower Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Cost and equity method investments [Member] Income Approach Valuation Technique [Member] Capitalization Rate Unobservable Inputs [Member] Upper Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Long Lived Assets, Including Real Estate [Member] Income Approach Valuation Technique [Member] Capitalization Rate Unobservable Inputs [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Long Lived Assets, Including Real Estate [Member] Income Approach Valuation Technique [Member] Capitalization Rate Unobservable Inputs [Member] Lower Limit [Member]	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member] Long Lived Assets, Including Real Estate [Member] Income Approach Valuation Technique [Member] Capitalization Rate Unobservable Inputs [Member] Upper Limit [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Domestic Corporate Debt Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Domestic Corporate Debt Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Asset-backed Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Asset-backed Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Foreign Corporate Debt Securities [Member]	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] Foreign Corporate Debt Securities [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member] Domestic Corporate Debt Securities [Member] Income Approach Valuation Technique [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member] Asset-backed Securities [Member] Income Approach Valuation Technique [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member] Foreign Corporate Debt Securities [Member] Income Approach Valuation Technique [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member] Other Items [Member] Income Approach Valuation Technique [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Nonrecurring [Member] Financing receivables and loans held for sale [Member] Income Approach Valuation Technique [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Nonrecurring [Member] Financing receivables and loans held for sale [Member] Business Enterprise Value Valuation Technique [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Nonrecurring [Member] Cost and equity method investments [Member] Income Approach Valuation Technique [Member]	Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Nonrecurring [Member] Long Lived Assets, Including Real Estate [Member] Income Approach Valuation Technique [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis, Valuation Techniques [Line Items]
Investments, Fair Value Disclosure																									$ 3,552	$ 3,235	$ 5,023	$ 4,040	$ 1,212	$ 1,204	$ 1,652	$ 4,977	$ 865	$ 360	$ 2,633	$ 202	$ 72	$ 985
Range Discount Rate Used For Level Three Valuation		1.30%	29.90%		2.10%	13.10%		1.50%	25.00%
Range EBITDA Multiple Used For Level Three Valuation																	2.0	6.0
Range Capitalization Rate Used For Level Three Valuation														3.80%	14.00%					9.20%	12.80%		4.80%	14.60%
Weighted Average Discount Rate Used For Level Three Valuation	11.10%			3.80%			13.20%
Weighted Average Cost Of Capital Used For Level Three Valuation										8.70%	8.70%	10.20%
Weighted Average EBITDA Multiple Used For Level Three Valuation																4.8
Weighted Average Capitalization Rate Used For Level Three Valuation													8.00%						12.00%			7.30%