Investments (Details Textuals 9) (USD $) In Millions, unless otherwise specified	Sep. 30, 2011	Dec. 31, 2010
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%	20.00%
% A Rated or Better	20.00%
Twelve months or greater [Member] | Non-redeemable preferred stock [Member] | 20% or more [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Temporary Loss	$ 85
Twelve months or greater [Member] | Non-redeemable preferred stock [Member] | 20% or more [Member] | Financial Services Industry [Member] | Investment Grade [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Temporary Loss	85
% A Rated or Better	72.00%
Twelve months or greater [Member] | 20% or more [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Temporary Loss	85	116
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Temporary Loss	228	241
Non-redeemable preferred stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Temporary Loss	$ 186	$ 229