Derivative Instruments- Impact of Derivative Instruments on Balance Sheet (Parenthetical) (Detail) (USD $)
In Millions, unless otherwise specified |
Jun. 30, 2013
|
Dec. 31, 2012
|
---|---|---|
Derivative Instruments and Hedging Activities Disclosure [Abstract] | ||
Master netting agreements, cash collateral received | $ 1,189 | $ 1,452 |
Master netting agreements, cash collateral paid | $ 156 | $ 131 |