Fair Value (Quantitative information about significant unobservable inputs in the fair value measurement of level 3 assets) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 42,852	$ 43,073
Fixed maturity securities [Member] | Income Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	95	142
Fixed maturity securities [Member] | Income Approach Valuation Technique [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit spread	2.00%	2.00%
Fixed maturity securities [Member] | Income Approach Valuation Technique [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit spread	12.00%	20.00%
Fixed maturity securities [Member] | Income Approach Valuation Technique [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit spread	3.00%	4.00%
Equity securities [Member] | Market Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	18	10
Equity securities [Member] | Market Approach Valuation Technique [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Private offering price	$ 13.00	$ 360.00
Equity securities [Member] | Market Approach Valuation Technique [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Private offering price	$ 4,388.00	$ 4,268.00
Equity securities [Member] | Market Approach Valuation Technique [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Private offering price	$ 544.00	$ 1,148.00
Life settlement contracts, included in Other assets [Member] | Income Approach Valuation Technique [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 86	$ 88
Life settlement contracts, included in Other assets [Member] | Income Approach Valuation Technique [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality assumption	70.00%	70.00%
Life settlement contracts, included in Other assets [Member] | Income Approach Valuation Technique [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality assumption	743.00%	743.00%
Life settlement contracts, included in Other assets [Member] | Income Approach Valuation Technique [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality assumption	193.00%	192.00%
Life settlement contracts, included in Other assets [Member] | Income Approach Valuation Technique [Member] | Rate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate risk premium	9.00%	9.00%