Fair Value (Details) (USD $) | Dec. 31, 2013 | Dec. 31, 2012 |
In Thousands, unless otherwise specified |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | $13,593,303 | $14,395,315 |
Short-term investments, trading securities, at fair value | 13,546 | 150,552 |
Equities, trading securities | 1,221,053 | 1,094,002 |
Other invested assets | 135,139 | 71,204 |
Funds held - directly managed | 561,306 | 833,247 |
Total | 15,524,347 | 16,544,320 |
Short-term investments [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Funds held - directly managed | 2,426 | ' |
Derivative assets [Member] | Foreign exchange forward contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 1,249 | 7,889 |
Derivative assets [Member] | Foreign currency option contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 1,410 |
Derivative assets [Member] | Futures contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 41,031 | 1,956 |
Derivative assets [Member] | Credit default swaps (protection purchased) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 6 |
Derivative assets [Member] | Credit default swaps (assumed risks) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 512 |
Derivative assets [Member] | Total return swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 79 | 6,630 |
Derivative assets [Member] | Interest rate swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 2,147 | ' |
Derivative assets [Member] | TBAs [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 2 | 115 |
Derivative liabilities [Member] | Foreign exchange forward contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -8,648 | -17,395 |
Derivative liabilities [Member] | Foreign currency option contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -535 | -186 |
Derivative liabilities [Member] | Futures contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | -1,352 |
Derivative liabilities [Member] | Credit default swaps (protection purchased) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -71 | -807 |
Derivative liabilities [Member] | Insurance-linked securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -268 | -2,173 |
Derivative liabilities [Member] | Total return swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -599 | -546 |
Derivative liabilities [Member] | Interest rate swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -2,558 | -7,880 |
Derivative liabilities [Member] | TBAs [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -1,331 | -163 |
Notes And Loan Receivables And Notes Securitization [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 41,446 | 34,902 |
Annuities and residuals [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 24,064 | 46,882 |
Private Equities Total [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 39,131 | 1,404 |
Other invested assets funds held directly managed [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Funds held - directly managed | 15,165 | 17,976 |
Real estate investment trust [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 175,796 | 66,846 |
Energy [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 159,509 | 118,213 |
Insurance [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 144,020 | 39,132 |
Finance [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 138,707 | 100,405 |
Consumer noncyclical [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 108,663 | 130,526 |
Communications [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 72,991 | 65,722 |
Technology [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 61,520 | 78,914 |
Industrials [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 47,677 | 59,242 |
Consumer cyclical [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 45,915 | 62,526 |
Utilities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 37,151 | ' |
Other equities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 19,993 | 60,913 |
Mutual funds and exchange traded funds [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 209,111 | 311,563 |
US Government and government sponsored enterpises [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 1,623,859 | 1,130,924 |
Funds held - directly managed | 157,296 | 218,696 |
US states, territories and municipalities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 124,587 | 243,386 |
Funds held - directly managed | 286 | 345 |
Non US sovereign government supranational and government related [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 2,353,699 | 2,375,673 |
Funds held - directly managed | 137,186 | 233,987 |
Corporate [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 6,048,663 | 6,655,838 |
Funds held - directly managed | 248,947 | 362,243 |
Asset-backed securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 1,138,231 | 723,470 |
Residential mortgage-backed securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 2,268,517 | 3,199,924 |
Other mortgage-backed securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 35,747 | 66,100 |
Quoted prices in active markets for identical assets (Level 1) | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 0 | 0 |
Short-term investments, trading securities, at fair value | 0 | 0 |
Equities, trading securities | 1,034,130 | 788,556 |
Other invested assets | 41,031 | 604 |
Funds held - directly managed | 0 | 0 |
Total | 1,075,161 | 789,160 |
Quoted prices in active markets for identical assets (Level 1) | Short-term investments [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Funds held - directly managed | 0 | ' |
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | Foreign exchange forward contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | Foreign currency option contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 0 |
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | Futures contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 41,031 | 1,956 |
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | Credit default swaps (protection purchased) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 0 |
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | Credit default swaps (assumed risks) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 0 |
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | Total return swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | Interest rate swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | ' |
Quoted prices in active markets for identical assets (Level 1) | Derivative assets [Member] | TBAs [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Foreign exchange forward contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Foreign currency option contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Futures contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | -1,352 |
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Credit default swaps (protection purchased) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Insurance-linked securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Total return swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | Interest rate swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Derivative liabilities [Member] | TBAs [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Notes And Loan Receivables And Notes Securitization [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Annuities and residuals [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Private Equities Total [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Other invested assets funds held directly managed [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Funds held - directly managed | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Real estate investment trust [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 175,796 | 66,846 |
Quoted prices in active markets for identical assets (Level 1) | Energy [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 159,509 | 118,213 |
Quoted prices in active markets for identical assets (Level 1) | Insurance [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 144,020 | 39,132 |
Quoted prices in active markets for identical assets (Level 1) | Finance [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 108,944 | 79,456 |
Quoted prices in active markets for identical assets (Level 1) | Consumer noncyclical [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 108,663 | 130,526 |
Quoted prices in active markets for identical assets (Level 1) | Communications [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 70,792 | 65,722 |
Quoted prices in active markets for identical assets (Level 1) | Technology [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 53,768 | 71,927 |
Quoted prices in active markets for identical assets (Level 1) | Industrials [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 47,677 | 59,242 |
Quoted prices in active markets for identical assets (Level 1) | Consumer cyclical [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 45,915 | 62,526 |
Quoted prices in active markets for identical assets (Level 1) | Utilities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 37,151 | ' |
Quoted prices in active markets for identical assets (Level 1) | Other equities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 19,993 | 60,913 |
Quoted prices in active markets for identical assets (Level 1) | Mutual funds and exchange traded funds [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 61,902 | 34,053 |
Quoted prices in active markets for identical assets (Level 1) | US Government and government sponsored enterpises [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 0 | 0 |
Funds held - directly managed | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | US states, territories and municipalities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 0 | 0 |
Funds held - directly managed | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Non US sovereign government supranational and government related [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 0 | 0 |
Funds held - directly managed | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Corporate [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 0 | 0 |
Funds held - directly managed | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Asset-backed securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Residential mortgage-backed securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 0 | 0 |
Quoted prices in active markets for identical assets (Level 1) | Other mortgage-backed securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 0 | 0 |
Significant other observable inputs (Level 2) | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 13,038,346 | 13,738,042 |
Short-term investments, trading securities, at fair value | 13,546 | 150,552 |
Equities, trading securities | 148,878 | 277,718 |
Other invested assets | -9,745 | -16,499 |
Funds held - directly managed | 545,855 | 814,926 |
Total | 13,736,880 | 14,964,739 |
Significant other observable inputs (Level 2) | Short-term investments [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Funds held - directly managed | 2,426 | ' |
Significant other observable inputs (Level 2) | Derivative assets [Member] | Foreign exchange forward contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 1,249 | 7,889 |
Significant other observable inputs (Level 2) | Derivative assets [Member] | Foreign currency option contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 1,410 |
Significant other observable inputs (Level 2) | Derivative assets [Member] | Futures contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant other observable inputs (Level 2) | Derivative assets [Member] | Credit default swaps (protection purchased) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 6 |
Significant other observable inputs (Level 2) | Derivative assets [Member] | Credit default swaps (assumed risks) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 512 |
Significant other observable inputs (Level 2) | Derivative assets [Member] | Total return swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant other observable inputs (Level 2) | Derivative assets [Member] | Interest rate swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 2,147 | ' |
Significant other observable inputs (Level 2) | Derivative assets [Member] | TBAs [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 2 | 115 |
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Foreign exchange forward contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -8,648 | -17,395 |
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Foreign currency option contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -535 | -186 |
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Futures contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 0 |
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Credit default swaps (protection purchased) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -71 | -807 |
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Insurance-linked securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Total return swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | Interest rate swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -2,558 | -7,880 |
Significant other observable inputs (Level 2) | Derivative liabilities [Member] | TBAs [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -1,331 | -163 |
Significant other observable inputs (Level 2) | Notes And Loan Receivables And Notes Securitization [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant other observable inputs (Level 2) | Annuities and residuals [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant other observable inputs (Level 2) | Private Equities Total [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant other observable inputs (Level 2) | Other invested assets funds held directly managed [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Funds held - directly managed | 0 | 0 |
Significant other observable inputs (Level 2) | Real estate investment trust [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant other observable inputs (Level 2) | Energy [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant other observable inputs (Level 2) | Insurance [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant other observable inputs (Level 2) | Finance [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 9,556 | 7,472 |
Significant other observable inputs (Level 2) | Consumer noncyclical [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant other observable inputs (Level 2) | Communications [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant other observable inputs (Level 2) | Technology [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant other observable inputs (Level 2) | Industrials [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant other observable inputs (Level 2) | Consumer cyclical [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant other observable inputs (Level 2) | Utilities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | ' |
Significant other observable inputs (Level 2) | Other equities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant other observable inputs (Level 2) | Mutual funds and exchange traded funds [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 139,322 | 270,246 |
Significant other observable inputs (Level 2) | US Government and government sponsored enterpises [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 1,623,859 | 1,130,924 |
Funds held - directly managed | 157,296 | 218,696 |
Significant other observable inputs (Level 2) | US states, territories and municipalities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 16,207 | 10,151 |
Funds held - directly managed | 0 | 0 |
Significant other observable inputs (Level 2) | Non US sovereign government supranational and government related [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 2,353,699 | 2,375,673 |
Funds held - directly managed | 137,186 | 233,987 |
Significant other observable inputs (Level 2) | Corporate [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 6,048,663 | 6,554,934 |
Funds held - directly managed | 248,947 | 362,243 |
Significant other observable inputs (Level 2) | Asset-backed securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 691,654 | 400,336 |
Significant other observable inputs (Level 2) | Residential mortgage-backed securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 2,268,517 | 3,199,924 |
Significant other observable inputs (Level 2) | Other mortgage-backed securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 35,747 | 66,100 |
Significant unobservable inputs (Level 3) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 554,957 | 657,273 |
Short-term investments, trading securities, at fair value | 0 | 0 |
Equities, trading securities | 38,045 | 27,728 |
Other invested assets | 103,853 | 87,099 |
Funds held - directly managed | 15,451 | 18,321 |
Total | 712,306 | 790,421 |
Significant unobservable inputs (Level 3) [Member] | Short-term investments [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Funds held - directly managed | 0 | ' |
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | Foreign exchange forward contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | Foreign currency option contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 0 |
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | Futures contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | Credit default swaps (protection purchased) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 0 |
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | Credit default swaps (assumed risks) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 0 |
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | Total return swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 79 | 6,630 |
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | Interest rate swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | ' |
Significant unobservable inputs (Level 3) [Member] | Derivative assets [Member] | TBAs [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Foreign exchange forward contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Foreign currency option contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Futures contracts [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | ' | 0 |
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Credit default swaps (protection purchased) [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Insurance-linked securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -268 | -2,173 |
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Total return swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | -599 | -546 |
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | Interest rate swaps [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Derivative liabilities [Member] | TBAs [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Notes And Loan Receivables And Notes Securitization [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 41,446 | 34,902 |
Significant unobservable inputs (Level 3) [Member] | Annuities and residuals [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 24,064 | 46,882 |
Significant unobservable inputs (Level 3) [Member] | Private Equities Total [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Other invested assets | 39,131 | 1,404 |
Significant unobservable inputs (Level 3) [Member] | Other invested assets funds held directly managed [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Funds held - directly managed | 15,165 | 17,976 |
Significant unobservable inputs (Level 3) [Member] | Real estate investment trust [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Energy [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Insurance [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Finance [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 20,207 | 13,477 |
Significant unobservable inputs (Level 3) [Member] | Consumer noncyclical [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Communications [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 2,199 | 0 |
Significant unobservable inputs (Level 3) [Member] | Technology [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 7,752 | 6,987 |
Significant unobservable inputs (Level 3) [Member] | Industrials [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Consumer cyclical [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Utilities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | ' |
Significant unobservable inputs (Level 3) [Member] | Other equities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Mutual funds and exchange traded funds [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Equities, trading securities | 7,887 | 7,264 |
Significant unobservable inputs (Level 3) [Member] | US Government and government sponsored enterpises [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 0 | 0 |
Funds held - directly managed | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | US states, territories and municipalities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 108,380 | 233,235 |
Funds held - directly managed | 286 | 345 |
Significant unobservable inputs (Level 3) [Member] | Non US sovereign government supranational and government related [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 0 | 0 |
Funds held - directly managed | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Corporate [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 0 | 100,904 |
Funds held - directly managed | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Asset-backed securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 446,577 | 323,134 |
Significant unobservable inputs (Level 3) [Member] | Residential mortgage-backed securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | 0 | 0 |
Significant unobservable inputs (Level 3) [Member] | Other mortgage-backed securities [Member] | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' |
Fixed maturities, trading securities | $0 | $0 |