Fair Value Measurements - Schedule of assets and liabilities that were accounted for at fair value (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Assets
Fixed maturities, at fair value	$ 29,806,144		$ 27,500,136
Equity securities, at fair value	960,368		1,040,237
Short-term investments, at fair value	281,887		456,288
Total investments available for sale	31,048,399		28,996,661
Liabilities
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable)	914,773		0
U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value			2,501,851
Corporate
Assets
Fixed maturities, at fair value			11,125,830
RMBS - Agency
Assets
Fixed maturities, at fair value			3,546,122
RMBS - Non-Agency
Assets
Fixed maturities, at fair value			398,768
CMBS
Assets
Fixed maturities, at fair value			1,246,795
CDO
Assets
Fixed maturities, at fair value			717,313
Other asset-backed securities
Assets
Fixed maturities, at fair value			1,242,104
U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value			1,845,812
Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value			4,875,541
Recurring
Assets
Fixed maturities, at fair value			27,500,136
Equity securities, at fair value	960,368		1,040,237
Short-term investments, at fair value	281,887		456,288
Total investments available for sale	31,048,399		28,996,661
Cash equivalents	1,385,127		1,061,150
Other investments	1,001,269		870,582
Other assets	74,471		26,145
Total assets accounted for at fair value	33,614,465		30,954,538
Liabilities
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable)	189,623	[1]
Financial instruments sold, but not yet purchased	35,062		28,861
Other liabilities	32,844		104,143
Total liabilities accounted for at fair value	257,529		133,004
Recurring | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value			2,501,851	[2]
Recurring | Corporate
Assets
Fixed maturities, at fair value			11,125,830
Recurring | RMBS - Agency
Assets
Fixed maturities, at fair value			3,546,122
Recurring | RMBS - Non-Agency
Assets
Fixed maturities, at fair value			398,768
Recurring | CMBS
Assets
Fixed maturities, at fair value			1,246,795
Recurring | CDO
Assets
Fixed maturities, at fair value			717,313
Recurring | Other asset-backed securities
Assets
Fixed maturities, at fair value			1,242,104
Recurring | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value			1,845,812
Recurring | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value			4,875,541
Recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Fixed maturities, at fair value			0
Equity securities, at fair value	589,321		540,331
Short-term investments, at fair value	0	[3],[4]	0	[3],[4]
Total investments available for sale	589,321		540,331
Cash equivalents	990,185	[5]	834,514	[5]
Other investments	0	[6]	0	[6]
Other assets	0	[7]	0	[7]
Total assets accounted for at fair value	1,580,976		1,374,845
Liabilities
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable)	0	[1]
Financial instruments sold, but not yet purchased	6,884	[8]	0	[8]
Other liabilities	0	[7]	0	[7]
Total liabilities accounted for at fair value	6,884		0
Recurring | Quoted prices in active markets for identical assets (Level 1) | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value			0
Recurring | Quoted prices in active markets for identical assets (Level 1) | Corporate
Assets
Fixed maturities, at fair value			0	[3]
Recurring | Quoted prices in active markets for identical assets (Level 1) | RMBS - Agency
Assets
Fixed maturities, at fair value			0
Recurring | Quoted prices in active markets for identical assets (Level 1) | RMBS - Non-Agency
Assets
Fixed maturities, at fair value			0
Recurring | Quoted prices in active markets for identical assets (Level 1) | CMBS
Assets
Fixed maturities, at fair value			0
Recurring | Quoted prices in active markets for identical assets (Level 1) | CDO
Assets
Fixed maturities, at fair value			0
Recurring | Quoted prices in active markets for identical assets (Level 1) | Other asset-backed securities
Assets
Fixed maturities, at fair value			0
Recurring | Quoted prices in active markets for identical assets (Level 1) | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value			0
Recurring | Quoted prices in active markets for identical assets (Level 1) | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value			0
Recurring | Significant other observable inputs (Level 2)
Assets
Fixed maturities, at fair value			26,723,418
Equity securities, at fair value	371,047		499,906
Short-term investments, at fair value	281,887	[3],[4]	454,273	[3],[4]
Total investments available for sale	29,691,011		27,677,597
Cash equivalents	394,942	[5]	226,636	[5]
Other investments	854,734	[6]	757,110	[6]
Other assets	70,453	[7]	27,487	[7]
Total assets accounted for at fair value	31,114,869		28,688,830
Liabilities
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable)	189,623	[1]
Financial instruments sold, but not yet purchased	28,178	[8]	28,861	[8]
Other liabilities	10,626	[7]	76,375	[7]
Total liabilities accounted for at fair value	228,427		105,236
Recurring | Significant other observable inputs (Level 2) | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value			2,501,851
Recurring | Significant other observable inputs (Level 2) | Corporate
Assets
Fixed maturities, at fair value			11,094,257	[3]
Recurring | Significant other observable inputs (Level 2) | RMBS - Agency
Assets
Fixed maturities, at fair value			3,535,649
Recurring | Significant other observable inputs (Level 2) | RMBS - Non-Agency
Assets
Fixed maturities, at fair value			398,759
Recurring | Significant other observable inputs (Level 2) | CMBS
Assets
Fixed maturities, at fair value			1,234,262
Recurring | Significant other observable inputs (Level 2) | CDO
Assets
Fixed maturities, at fair value			7,060
Recurring | Significant other observable inputs (Level 2) | Other asset-backed securities
Assets
Fixed maturities, at fair value			1,230,227
Recurring | Significant other observable inputs (Level 2) | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value			1,845,812
Recurring | Significant other observable inputs (Level 2) | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value			4,875,541
Recurring | Significant other unobservable inputs (Level 3)
Assets
Fixed maturities, at fair value			776,718
Equity securities, at fair value	0		0
Short-term investments, at fair value	0	[3],[4]	2,015	[3],[4]
Total investments available for sale	768,067		778,733
Cash equivalents	0	[5]	0	[5]
Other investments	146,535	[6]	113,472	[6]
Other assets	11,597	[7]	0	[7]
Total assets accounted for at fair value	926,199		892,205
Liabilities
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable)	0	[1]
Financial instruments sold, but not yet purchased	0	[8]	0	[8]
Other liabilities	29,797	[7]	29,110	[7]
Total liabilities accounted for at fair value	29,797		29,110
Recurring | Significant other unobservable inputs (Level 3) | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value			0
Recurring | Significant other unobservable inputs (Level 3) | Corporate
Assets
Fixed maturities, at fair value			31,573	[3]
Recurring | Significant other unobservable inputs (Level 3) | RMBS - Agency
Assets
Fixed maturities, at fair value			10,473
Recurring | Significant other unobservable inputs (Level 3) | RMBS - Non-Agency
Assets
Fixed maturities, at fair value			9
Recurring | Significant other unobservable inputs (Level 3) | CMBS
Assets
Fixed maturities, at fair value			12,533
Recurring | Significant other unobservable inputs (Level 3) | CDO
Assets
Fixed maturities, at fair value			710,253
Recurring | Significant other unobservable inputs (Level 3) | Other asset-backed securities
Assets
Fixed maturities, at fair value			11,877
Recurring | Significant other unobservable inputs (Level 3) | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value			0
Recurring | Significant other unobservable inputs (Level 3) | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value			0
Recurring | Collateral and counterparty netting
Assets
Fixed maturities, at fair value			0
Equity securities, at fair value	0		0
Short-term investments, at fair value	0	[3],[4]	0	[3],[4]
Total investments available for sale	0		0
Cash equivalents	0	[5]	0	[5]
Other investments	0	[6]	0	[6]
Other assets	(7,579)	[7]	(1,342)	[7]
Total assets accounted for at fair value	(7,579)		(1,342)
Liabilities
Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable)	0	[1]
Financial instruments sold, but not yet purchased	0	[8]	0	[8]
Other liabilities	(7,579)	[7]	(1,342)	[7]
Total liabilities accounted for at fair value	(7,579)		(1,342)
Recurring | Collateral and counterparty netting | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value			0
Recurring | Collateral and counterparty netting | Corporate
Assets
Fixed maturities, at fair value			0	[3]
Recurring | Collateral and counterparty netting | RMBS - Agency
Assets
Fixed maturities, at fair value			0
Recurring | Collateral and counterparty netting | RMBS - Non-Agency
Assets
Fixed maturities, at fair value			0
Recurring | Collateral and counterparty netting | CMBS
Assets
Fixed maturities, at fair value			0
Recurring | Collateral and counterparty netting | CDO
Assets
Fixed maturities, at fair value			0
Recurring | Collateral and counterparty netting | Other asset-backed securities
Assets
Fixed maturities, at fair value			0
Recurring | Collateral and counterparty netting | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value			0
Recurring | Collateral and counterparty netting | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value			0
Excluding Life Funds Withheld Assets
Assets
Fixed maturities, at fair value	24,543,059
Total investments available for sale	25,785,314
Excluding Life Funds Withheld Assets | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value	2,127,508
Excluding Life Funds Withheld Assets | Corporate
Assets
Fixed maturities, at fair value	9,427,025
Excluding Life Funds Withheld Assets | RMBS - Agency
Assets
Fixed maturities, at fair value	3,334,882
Excluding Life Funds Withheld Assets | RMBS - Non-Agency
Assets
Fixed maturities, at fair value	435,654
Excluding Life Funds Withheld Assets | CMBS
Assets
Fixed maturities, at fair value	1,099,253
Excluding Life Funds Withheld Assets | CDO
Assets
Fixed maturities, at fair value	746,635
Excluding Life Funds Withheld Assets | Other asset-backed securities
Assets
Fixed maturities, at fair value	1,157,465
Excluding Life Funds Withheld Assets | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value	1,981,459
Excluding Life Funds Withheld Assets | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value	4,233,178
Excluding Life Funds Withheld Assets | Recurring
Assets
Fixed maturities, at fair value	24,543,059
Total investments available for sale	25,785,314
Excluding Life Funds Withheld Assets | Recurring | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value	2,127,508
Excluding Life Funds Withheld Assets | Recurring | Corporate
Assets
Fixed maturities, at fair value	9,427,025
Excluding Life Funds Withheld Assets | Recurring | RMBS - Agency
Assets
Fixed maturities, at fair value	3,334,882
Excluding Life Funds Withheld Assets | Recurring | RMBS - Non-Agency
Assets
Fixed maturities, at fair value	435,654
Excluding Life Funds Withheld Assets | Recurring | CMBS
Assets
Fixed maturities, at fair value	1,099,253
Excluding Life Funds Withheld Assets | Recurring | CDO
Assets
Fixed maturities, at fair value	746,635
Excluding Life Funds Withheld Assets | Recurring | Other asset-backed securities
Assets
Fixed maturities, at fair value	1,157,465
Excluding Life Funds Withheld Assets | Recurring | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value	1,981,459
Excluding Life Funds Withheld Assets | Recurring | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value	4,233,178
Excluding Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Fixed maturities, at fair value	0
Total investments available for sale	589,321
Excluding Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | Corporate
Assets
Fixed maturities, at fair value	0	[3]
Excluding Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | RMBS - Agency
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | RMBS - Non-Agency
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | CMBS
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | CDO
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | Other asset-backed securities
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2)
Assets
Fixed maturities, at fair value	23,774,992
Total investments available for sale	24,427,926
Excluding Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value	2,127,508
Excluding Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | Corporate
Assets
Fixed maturities, at fair value	9,419,983	[3]
Excluding Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | RMBS - Agency
Assets
Fixed maturities, at fair value	3,328,400
Excluding Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | RMBS - Non-Agency
Assets
Fixed maturities, at fair value	435,644
Excluding Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | CMBS
Assets
Fixed maturities, at fair value	1,099,253
Excluding Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | CDO
Assets
Fixed maturities, at fair value	4,152
Excluding Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | Other asset-backed securities
Assets
Fixed maturities, at fair value	1,145,415
Excluding Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value	1,981,459
Excluding Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value	4,233,178
Excluding Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3)
Assets
Fixed maturities, at fair value	768,067
Total investments available for sale	768,067
Excluding Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | Corporate
Assets
Fixed maturities, at fair value	7,042	[3]
Excluding Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | RMBS - Agency
Assets
Fixed maturities, at fair value	6,482
Excluding Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | RMBS - Non-Agency
Assets
Fixed maturities, at fair value	10
Excluding Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | CMBS
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | CDO
Assets
Fixed maturities, at fair value	742,483
Excluding Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | Other asset-backed securities
Assets
Fixed maturities, at fair value	12,050
Excluding Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Collateral and counterparty netting
Assets
Fixed maturities, at fair value	0
Total investments available for sale	0
Excluding Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | Corporate
Assets
Fixed maturities, at fair value	0	[3]
Excluding Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | RMBS - Agency
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | RMBS - Non-Agency
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | CMBS
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | CDO
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | Other asset-backed securities
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value	0
Excluding Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets
Assets
Fixed maturities, at fair value	5,263,085		0
Life Funds Withheld Assets | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value	18,326
Life Funds Withheld Assets | Corporate
Assets
Fixed maturities, at fair value	2,898,684
Life Funds Withheld Assets | RMBS - Agency
Assets
Fixed maturities, at fair value	3,896
Life Funds Withheld Assets | RMBS - Non-Agency
Assets
Fixed maturities, at fair value	86,542
Life Funds Withheld Assets | CMBS
Assets
Fixed maturities, at fair value	200,348
Life Funds Withheld Assets | CDO
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Other asset-backed securities
Assets
Fixed maturities, at fair value	278,229
Life Funds Withheld Assets | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value	1,777,060
Life Funds Withheld Assets | Recurring
Assets
Fixed maturities, at fair value	5,263,085
Cash equivalents	105,199
Life Funds Withheld Assets | Recurring | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value	18,326
Life Funds Withheld Assets | Recurring | Corporate
Assets
Fixed maturities, at fair value	2,898,684
Life Funds Withheld Assets | Recurring | RMBS - Agency
Assets
Fixed maturities, at fair value	3,896
Life Funds Withheld Assets | Recurring | RMBS - Non-Agency
Assets
Fixed maturities, at fair value	86,542
Life Funds Withheld Assets | Recurring | CMBS
Assets
Fixed maturities, at fair value	200,348
Life Funds Withheld Assets | Recurring | CDO
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Other asset-backed securities
Assets
Fixed maturities, at fair value	278,229
Life Funds Withheld Assets | Recurring | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value	1,777,060
Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Fixed maturities, at fair value	0
Cash equivalents	1,470	[5]
Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | Corporate
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | RMBS - Agency
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | RMBS - Non-Agency
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | CMBS
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | CDO
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | Other asset-backed securities
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Quoted prices in active markets for identical assets (Level 1) | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2)
Assets
Fixed maturities, at fair value	5,263,085
Cash equivalents	103,729	[5]
Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value	18,326
Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | Corporate
Assets
Fixed maturities, at fair value	2,898,684
Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | RMBS - Agency
Assets
Fixed maturities, at fair value	3,896
Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | RMBS - Non-Agency
Assets
Fixed maturities, at fair value	86,542
Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | CMBS
Assets
Fixed maturities, at fair value	200,348
Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | CDO
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | Other asset-backed securities
Assets
Fixed maturities, at fair value	278,229
Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Significant other observable inputs (Level 2) | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value	1,777,060
Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3)
Assets
Fixed maturities, at fair value	0
Cash equivalents	0	[5]
Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | Corporate
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | RMBS - Agency
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | RMBS - Non-Agency
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | CMBS
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | CDO
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | Other asset-backed securities
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Significant other unobservable inputs (Level 3) | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Collateral and counterparty netting
Assets
Fixed maturities, at fair value	0
Cash equivalents	0	[5]
Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | U.S. Government and Government - Related/Supported
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | Corporate
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | RMBS - Agency
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | RMBS - Non-Agency
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | CMBS
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | CDO
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | Other asset-backed securities
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | U.S. States and political subdivisions of the States
Assets
Fixed maturities, at fair value	0
Life Funds Withheld Assets | Recurring | Collateral and counterparty netting | Non-U.S. Sovereign Government, Provincial, Supranational, and Government-Related/Supported
Assets
Fixed maturities, at fair value	$ 0

[1] Funds withheld on life retrocession arrangements (net of future policy benefit reserves recoverable) include balances related to the life retrocession embedded derivative, under which all investment results associated with the Life Funds Withheld Assets related the Life Retro Arrangements described in Note 3, ”Sale of Life Reinsurance Subsidiary”, accrue to the benefit of GreyCastle.

[2] Represents the non-credit component of OTTI losses, adjusted for subsequent sales of securities. It does not include the change in fair value subsequent to the date an impairment was recorded.

[3] Included within Corporate are certain medium term notes supported primarily by pools of European investment grade credit with varying degrees of leverage. The notes had a fair value of $152.4 million and $154.6 million and an amortized cost of $141.1 million and $147.7 million at September 30, 2014 and December 31, 2013, respectively. These notes allow the investor to participate in cash flows of the underlying bonds including certain residual values, which could serve to either decrease or increase the ultimate values of these notes.

[4] Short-term investments consist primarily of Corporate securities and U.S. and Non-U.S. Government and Government-Related/Supported securities.

[5] Cash equivalents balances subject to fair value measurement include certificates of deposit and money market funds. Operating cash balances are not subject to recurring fair value measurement guidance.

[6] The Other investments balance excludes certain structured transactions including certain investments in project finance transactions, a payment obligation and liquidity financing provided to a structured credit vehicle as a part of a third party medium term note facility. These investments, which totaled $276.2 million at September 30, 2014 and $294.0 million at December 31, 2013, are carried at amortized cost. For further information, see Item 8, Note 7, “Other Investments,” to the Consolidated Financial Statements included in our Annual Report on Form 10-K for the year ended December 31, 2013.

[7] Other assets and other liabilities include derivative instruments. The derivative balances included in each category are reported on a gross basis by level with a netting adjustment presented separately in the Collateral and Counterparty Netting column. The fair values of the individual derivative contracts are reported gross in their respective levels based on the fair value hierarchy. For further details regarding derivative fair values and associated collateral received or paid see Note 7, “Derivative Instruments,” to the Unaudited Consolidated Financial Statements.

[8] Financial instruments sold, but not yet purchased, represent “short sales” and are included within “Payable for investments purchased” on the balance sheets.