Derivative Financial Instruments (Credit Derivatives-Selling Protection) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014 entity	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Term of credit default swaps (in years)	5 years
Credit Derivatives
Notional amount	$ 3,770	$ 12,409
The number of reference entities generally included in a CDX index	125
Credit default swaps
Credit Derivatives
Notional amount	180	185
Fair value	(7)	(13)
Credit default swaps | Single name | Corporate debt
Credit Derivatives
Notional amount	0	5
Fair value	0	0
Credit default swaps | First-to-default Basket | Municipal
Credit Derivatives
Notional amount	100	100
Fair value	(9)	(15)
Credit default swaps | Index | Corporate debt
Credit Derivatives
Notional amount	80	80
Fair value	2	2
AA | Credit default swaps
Credit Derivatives
Notional amount	1	1
AA | Credit default swaps | Single name | Corporate debt
Credit Derivatives
Notional amount	0	0
AA | Credit default swaps | First-to-default Basket | Municipal
Credit Derivatives
Notional amount	0	0
AA | Credit default swaps | Index | Corporate debt
Credit Derivatives
Notional amount	1	1
A | Credit default swaps
Credit Derivatives
Notional amount	126	125
A | Credit default swaps | Single name | Corporate debt
Credit Derivatives
Notional amount	0	5
A | Credit default swaps | First-to-default Basket | Municipal
Credit Derivatives
Notional amount	100	100
A | Credit default swaps | Index | Corporate debt
Credit Derivatives
Notional amount	26	20
BBB | Credit default swaps
Credit Derivatives
Notional amount	50	55
BBB | Credit default swaps | Single name | Corporate debt
Credit Derivatives
Notional amount	0	0
BBB | Credit default swaps | First-to-default Basket | Municipal
Credit Derivatives
Notional amount	0	0
BBB | Credit default swaps | Index | Corporate debt
Credit Derivatives
Notional amount	50	55
BB and lower | Credit default swaps
Credit Derivatives
Notional amount	3	4
BB and lower | Credit default swaps | Single name | Corporate debt
Credit Derivatives
Notional amount	0	0
BB and lower | Credit default swaps | First-to-default Basket | Municipal
Credit Derivatives
Notional amount	0	0
BB and lower | Credit default swaps | Index | Corporate debt
Credit Derivatives
Notional amount	$ 3	$ 4