|
Fair Value Measurements (Narrative) (Details) (USD $)
|
6 Months Ended | 3 Months Ended | 6 Months Ended | 3 Months Ended | 6 Months Ended | 0 Months Ended | 0 Months Ended | 6 Months Ended | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Jun. 30, 2012
|
Jun. 30, 2011
|
Dec. 31, 2011
|
Jun. 30, 2012
Other Investments [Member]
Investment Income, Net [Member]
|
Jun. 30, 2011
Other Investments [Member]
Investment Income, Net [Member]
|
Jun. 30, 2012
Other Investments [Member]
Investment Income, Net [Member]
|
Jun. 30, 2011
Other Investments [Member]
Investment Income, Net [Member]
|
Jun. 30, 2012
Other Assets and Liabilities [Member]
Other (Loss) Income [Member]
|
Jun. 30, 2011
Other Assets and Liabilities [Member]
Other (Loss) Income [Member]
|
Jun. 30, 2012
Other Assets and Liabilities [Member]
Other (Loss) Income [Member]
|
Jun. 30, 2011
Other Assets and Liabilities [Member]
Other (Loss) Income [Member]
|
Jan. 03, 2003
5.875% Senior Notes Due February 15, 2013 [Member]
|
Jun. 30, 2012
5.875% Senior Notes Due February 15, 2013 [Member]
|
Dec. 31, 2011
5.875% Senior Notes Due February 15, 2013 [Member]
|
Mar. 17, 2010
5.75% Senior Notes Due March 15, 2020 [Member]
RenRe North America Holdings Inc. [Member]
|
Jun. 30, 2012
5.75% Senior Notes Due March 15, 2020 [Member]
RenRe North America Holdings Inc. [Member]
|
Dec. 31, 2011
5.75% Senior Notes Due March 15, 2020 [Member]
RenRe North America Holdings Inc. [Member]
|
Jun. 30, 2012
U.S. treasuries [Member]
|
Dec. 31, 2011
U.S. treasuries [Member]
|
Jun. 30, 2012
Agencies [Member]
|
Dec. 31, 2011
Agencies [Member]
|
Jun. 30, 2012
Non-U.S. government (Sovereign Debt) [Member]
|
Dec. 31, 2011
Non-U.S. government (Sovereign Debt) [Member]
|
Jun. 30, 2012
FDIC guaranteed corporate [Member]
|
Dec. 31, 2011
FDIC guaranteed corporate [Member]
|
Jun. 30, 2012
Non-U.S. government-backed corporate [Member]
|
Dec. 31, 2011
Non-U.S. government-backed corporate [Member]
|
Jun. 30, 2012
Corporate [Member]
|
Dec. 31, 2011
Corporate [Member]
|
Jun. 30, 2012
Agency mortgage-backed [Member]
years
|
Dec. 31, 2011
Agency mortgage-backed [Member]
years
|
Jun. 30, 2012
Non-agency prime residential mortgage-backed [Member]
years
|
Dec. 31, 2011
Non-agency prime residential mortgage-backed [Member]
years
|
Jun. 30, 2012
AltA non-agency mortgage-backed [Member]
years
|
Dec. 31, 2011
AltA non-agency mortgage-backed [Member]
years
|
Jun. 30, 2012
Commercial mortgage-backed [Member]
years
|
Dec. 31, 2011
Commercial mortgage-backed [Member]
years
|
Jun. 30, 2012
Asset-backed [Member]
years
|
Dec. 31, 2011
Asset-backed [Member]
years
|
Jun. 30, 2012
Private equity partnerships [Member]
|
Jun. 30, 2012
Senior secured bank loan funds [Member]
|
Jun. 30, 2012
Hedge funds [Member]
|
Jun. 30, 2012
Assumed and ceded reinsurance contracts [Member]
|
Dec. 31, 2011
Assumed and ceded reinsurance contracts [Member]
|
Jun. 30, 2012
Other [Member]
|
Dec. 31, 2011
Other [Member]
|
Jun. 30, 2012
Miscellaneous other investments [Member]
|
Dec. 31, 2011
Miscellaneous other investments [Member]
|
Jun. 30, 2012
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
|
Dec. 31, 2011
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
|
Jun. 30, 2012
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Assumed and ceded reinsurance contracts [Member]
|
Dec. 31, 2011
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Assumed and ceded reinsurance contracts [Member]
|
Jun. 30, 2012
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Other [Member]
|
Dec. 31, 2011
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Other [Member]
|
Jun. 30, 2012
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Cash Settled Restricted Stock Unit [Member]
|
Jun. 30, 2012
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Miscellaneous other investments [Member]
|
Dec. 31, 2011
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Miscellaneous other investments [Member]
|
Jun. 30, 2012
Significant Unobservable Inputs (Level 3) [Member]
|
Dec. 31, 2011
Significant Unobservable Inputs (Level 3) [Member]
|
Jun. 30, 2012
Significant Unobservable Inputs (Level 3) [Member]
Assumed and ceded reinsurance contracts [Member]
|
Dec. 31, 2011
Significant Unobservable Inputs (Level 3) [Member]
Assumed and ceded reinsurance contracts [Member]
|
Jun. 30, 2012
Significant Unobservable Inputs (Level 3) [Member]
Other [Member]
|
Dec. 31, 2011
Significant Unobservable Inputs (Level 3) [Member]
Other [Member]
|
Jun. 30, 2012
Significant Unobservable Inputs (Level 3) [Member]
Miscellaneous other investments [Member]
|
Dec. 31, 2011
Significant Unobservable Inputs (Level 3) [Member]
Miscellaneous other investments [Member]
|
|
| Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Weighted average effective yield | 0.50% | 0.60% | 0.70% | 0.50% | 2.20% | 2.30% | 0.30% | 0.30% | 1.20% | 1.40% | 3.10% | 4.20% | 1.50% | 1.50% | 5.20% | 8.00% | 7.00% | 9.10% | 2.50% | 3.20% | 2.50% | 0.90% | |||||||||||||||||||||||||||||||||||||||||||
| Weighted average life | 2.8 | 2.6 | 5.2 | 3.3 | 5.5 | 3.8 | 3.8 | 4.2 | 3.8 | 1.8 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Investment in closed end fund | $ 22,700,000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Senior Notes, Carrying value | 100,000,000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Senior notes interest rate | 5.875% | 5.75% | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Debt instrument maturity date | February 15, 2013 | March 15, 2020 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Senior Notes, Fair value | 102,200,000 | 103,400,000 | 264,100,000 | 263,000,000 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Debt instrument, Face amount | 250,000,000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Net unrealized gains (losses) recognized in earnings | 23,821,000 | 22,270,000 | (13,400,000) | 5,700,000 | 21,900,000 | 33,700,000 | (400,000) | (800,000) | (2,500,000) | 43,300,000 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Investments redeemable in part, on a monthly basis, or in whole over a three month period | 246,600,000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Assets and (liabilities) at fair value | 35,252,000 | 16,071,000 | 9,689,000 | 2,115,000 | 10,811,000 | 10,644,000 | (2,593,000) | (6,162,000) | 0 | 0 | (4,604,000) | (6,869,000) | (4,600,000) | 34,185,000 | 28,526,000 | 9,689,000 | 2,115,000 | 15,415,000 | 17,513,000 | ||||||||||||||||||||||||||||||||||||||||||||||
| Estimated liquidation period of limited partnership assets, Minimum | 7 years | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Estimated liquidation period of limited partnership assets, Maximum | 10 years | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Other investments measured using net asset valuations | 635,828,000 | 360,268,000 | 269,317,000 | 6,243,000 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Hedge fund side pocket investments | 6,200,000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Other investments | 743,568,000 | 748,984,000 | 1,270,000 | 2,000,000 | 0 | 0 | 0 | 0 | 390,505,000 | 396,526,000 | 1,270,000 | 2,000,000 | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Assets (Liabilities), Fair Value Disclosure, Recurring | $ 34,185,000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||