v2.4.0.8
Fair Value, Investments in Entities That Calculate Net Asset Value Per Share (Details) (USD $)
In Millions, unless otherwise specified
6 Months Ended 12 Months Ended
Jun. 30, 2013
Dec. 31, 2012
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair value $ 1,281 $ 1,271
Unfunded commitments 212 216
Offshore Funds [Member]
   
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair value 439 379
Unfunded commitments 0 0
Redemption frequency Daily - Quarterly Daily - Annually
Redemption notice period 1 - 180 days 1 - 180 days
Funds of funds [Member]
   
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair value 0 1
Unfunded commitments 0 0
Redemption frequency  - Quarterly
Redemption notice period  - 90 days
Hedge Funds [Member]
   
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair value 4 2
Unfunded commitments 0 0
Redemption frequency Monthly - Semi Annually Daily - Annually
Redemption notice period 5 - 95 days 5 - 95 days
Private Equity Funds [Member]
   
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair value 758 807
Unfunded commitments 196 195
Redemption frequency N/A N/A
Redemption notice period N/A N/A
Venture Capital Funds [Member]
   
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]    
Fair value 80 82
Unfunded commitments $ 16 $ 21
Redemption frequency N/A N/A
Redemption notice period N/A N/A