SCHEDULE I - Consolidated Summary of Investments Other Than Investments in Related Parties (Details) $ in Thousands	Dec. 31, 2015 USD ($)
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Investments Not Carried At Fair Value	$ 208,000
Trading securities [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Fair value	14,129,710	[1]
Amount at which shown in the balance sheet	14,129,710	[1]
Trading securities [Member] | Fixed maturities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	13,313,819	[1],[2]
Fair value	13,448,262	[1]
Amount at which shown in the balance sheet	13,448,262	[1]
Trading securities [Member] | Fixed maturities | U.S. government and government sponsored enterprises
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	2,887,000	[1],[2]
Fair value	2,872,845	[1]
Amount at which shown in the balance sheet	2,872,845	[1]
Trading securities [Member] | Fixed maturities | U.S. states, territories and municipalities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	743,413	[1],[2]
Fair value	778,326	[1]
Amount at which shown in the balance sheet	778,326	[1]
Trading securities [Member] | Fixed maturities | Non-U.S. sovereign government, supranational and government related
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	1,271,416	[1],[2]
Fair value	1,332,925	[1]
Amount at which shown in the balance sheet	1,332,925	[1]
Trading securities [Member] | Fixed maturities | Corporate
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	5,035,006	[1],[2]
Fair value	5,086,199	[1]
Amount at which shown in the balance sheet	5,086,199	[1]
Trading securities [Member] | Fixed maturities | Asset-backed securities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	1,040,144	[1],[2]
Fair value	1,037,816	[1]
Amount at which shown in the balance sheet	1,037,816	[1]
Trading securities [Member] | Fixed maturities | Residential mortgage-backed securities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	2,287,173	[1],[2]
Fair value	2,290,640	[1]
Amount at which shown in the balance sheet	2,290,640	[1]
Trading securities [Member] | Fixed maturities | Other mortgage-backed securities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	49,667	[1],[2]
Fair value	49,511	[1]
Amount at which shown in the balance sheet	49,511	[1]
Trading securities [Member] | Equities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	418,428	[1],[2]
Fair value	443,861	[1]
Amount at which shown in the balance sheet	443,861	[1]
Trading securities [Member] | Equities | Banks, trust and insurance companies
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	89,934	[1],[2]
Fair value	137,704	[1]
Amount at which shown in the balance sheet	137,704	[1]
Trading securities [Member] | Equities | Public utilities
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	8,501	[1],[2]
Fair value	7,796	[1]
Amount at which shown in the balance sheet	7,796	[1]
Trading securities [Member] | Equities | Industrial, miscellaneous and all other
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	319,993	[1],[2]
Fair value	298,361	[1]
Amount at which shown in the balance sheet	298,361	[1]
Trading securities [Member] | Short-term investments
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Cost	46,689	[1],[2]
Fair value	46,688	[1]
Amount at which shown in the balance sheet	46,688	[1]
Trading securities [Member] | Other invested assets [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Fair value	190,899	[1],[3]
Amount at which shown in the balance sheet	$ 190,899	[1],[3]

[1] Excludes the investment portfolio underlying the funds held – directly managed account. While the net investment income and net realized and unrealized gains and losses inure to the benefit of the Company, the Company does not legally own the investments.

[2] Original cost of fixed maturities reduced by repayments and adjusted for amortization of premiums or accrual of discounts. Original cost of equity securities.

[3] Other invested assets excludes the Company’s investments accounted for using the cost method of accounting and the equity method of accounting of $208 million.