Investments (Evaluation of Available-For-Sale Securities for OTTI and Evaluating Temporarily Impaired AFS Securities - Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Equity securities available-for-sale with gross unrealized loss of equal to or greater than stated percentage	20.00%
Fixed maturity securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in Gross Unrealized Temporary Loss	$ 1,800
Gross Unrealized Temporary Loss	2,800	4,600
Gross Unrealized Temporary Loss	1,033	1,220
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Change in Gross Unrealized Temporary Loss	(15)
Gross Unrealized Temporary Loss	102	117
Gross Unrealized Temporary Loss	50	48
Non-redeemable preferred stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Temporary Loss	39	47
20% or more [Member] | Six months or greater [Member] | Fixed maturity securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Temporary Loss	231
Number of Securities	74
20% or more [Member] | Six months or greater [Member] | Fixed maturity securities [Member] | Investment Grade [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Temporary Loss	122
Number of Securities	48
Percentage of gross unrealized loss	53.00%
20% or more [Member] | Six months or greater [Member] | Fixed maturity securities [Member] | Below Investment Grade [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Temporary Loss	109
Number of Securities	26
Percentage of gross unrealized loss	47.00%
20% or more [Member] | Twelve months or greater [Member] | Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of Securities	12
Gross Unrealized Temporary Loss	$ 33
20% or more [Member] | Twelve months or greater [Member] | Non-redeemable preferred stock [Member] | Aaa/Aa/A [Member] | Financial Services Industry [Member]
Schedule of Available-for-sale Securities [Line Items]
Percentage of gross unrealized loss	64.00%