Summary of Investments (Tables)

3 Months Ended

Mar. 31, 2017

Investments, Debt and Equity Securities [Abstract]

Summary of fixed maturity investments classified as available-for-sale and the non-credit related components of other-than-temporary impairments (OTTI) in accumulated other comprehensive income (loss) (AOCI)

The following tables summarize fixed maturity investments classified as available-for-sale and the non-credit-related component of other-than-temporary impairments (“OTTI”) in accumulated other comprehensive income (loss) (“AOCI”):



	March 31, 2017
	Amortized		Gross unrealized		Gross unrealized		Estimated fair value		OTTI (gain) loss
Fixed maturities:	cost		gains		losses		and carrying value		included in AOCI ⁽¹⁾
U.S. government direct obligations and U.S. agencies	$	1,813,394	$	46,163	$	19,189	$	1,840,368	$	—
Obligations of U.S. states and their subdivisions	1,889,794		215,426		5,121		2,100,099		—
Corporate debt securities ⁽²⁾	14,270,203		512,816		229,442		14,553,577		(1,248		)
Asset-backed securities	1,443,721		101,214		16,671		1,528,264		(70,463		)
Residential mortgage-backed securities	124,522		4,200		996		127,726		(106		)
Commercial mortgage-backed securities	1,353,588		23,313		18,836		1,358,065		—
Collateralized debt obligations	532,580		1,693		36		534,237		—
Total fixed maturities	$	21,427,802	$	904,825	$	290,291	$	22,042,336	$	(71,817	)

⁽¹⁾ Indicates the amount of any OTTI (gain) loss included in AOCI that is included in gross unrealized gains and losses. OTTI (gain) loss included in AOCI, as presented above, includes both the initial recognition of non-credit losses and the effects of subsequent increases and decreases in estimated fair value for those fixed maturity securities with previous non-credit impairment. The non-credit loss component of OTTI (gain) loss was in an unrealized gain position due to increases in estimated fair value subsequent to initial recognition of non-credit losses on such securities.

⁽²⁾ Includes perpetual debt investments with amortized cost of $115,037 and estimated fair value of $105,162.



	December 31, 2016
	Amortized		Gross unrealized		Gross unrealized		Estimated fair value		OTTI (gain) loss
Fixed maturities:	cost		gains		losses		and carrying value		included in AOCI ⁽¹⁾
U.S. government direct obligations and U.S. agencies	$	3,022,279	$	47,791	$	34,958	$	3,035,112	$	—
Obligations of U.S. states and their subdivisions	1,890,568		214,411		6,317		2,098,662		—
Corporate debt securities ⁽²⁾	13,811,597		477,316		309,164		13,979,749		(1,488		)
Asset-backed securities	1,226,493		104,274		18,388		1,312,379		(72,464		)
Residential mortgage-backed securities	138,292		3,867		1,167		140,992		23
Commercial mortgage-backed securities	1,222,257		23,207		20,182		1,225,282		—
Collateralized debt obligations	361,241		339		53		361,527		—
Total fixed maturities	$	21,672,727	$	871,205	$	390,229	$	22,153,703	$	(73,929	)

⁽²⁾ Includes perpetual debt investments with amortized cost of $135,187 and estimated fair value of $113,239.

Schedule of amortized cost and estimated fair value of fixed maturity investments classified as available-for-sale

The amortized cost and estimated fair value of fixed maturity investments classified as available-for-sale, based on estimated cash flows, are shown in the table below. Actual maturities will likely differ from these projections because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.



	March 31, 2017
	Amortized cost		Estimated fair value
Maturing in one year or less	$	644,280	$	662,742
Maturing after one year through five years	3,845,273		4,018,406
Maturing after five years through ten years	6,950,269		7,068,702
Maturing after ten years	5,073,643		5,282,788
Mortgage-backed and asset-backed securities	4,914,337		5,009,698
Total fixed maturities	$	21,427,802	$	22,042,336

Summary of information regarding the sales of securities classified as available-for-sale

The following table summarizes information regarding the sales of securities classified as available-for-sale:



	Three Months Ended March 31,
	2017		2016
Proceeds from sales	$	1,580,522	$	1,682,893
Gross realized gains from sales	12,433		19,857
Gross realized losses from sales	15,257		11

Schedule of the carrying value of the mortgage loan portfolio by component

The following table summarizes the carrying value of the mortgage loan portfolio by component:



	March 31, 2017			December 31, 2016
Principal	$	3,843,130		$	3,558,863
Unamortized premium (discount) and fees, net	4,909			5,541
Foreign exchange translation	(1,799		)	(2,696		)
Mortgage provision allowance	(1,309		)	(2,882		)
Total mortgage loans	$	3,844,931		$	3,558,826

Summary of financing receivable credit quality indicators

The following table summarizes the recorded investment of the mortgage loan portfolio by risk assessment category as of March 31, 2017, and December 31, 2016, respectively:



	March 31, 2017		December 31, 2016
Performing	$	3,844,775	$	3,560,243
Non-performing	1,465		1,465
Total	$	3,846,240	$	3,561,708

Summary of activity in the mortgage provision allowance

The following table summarizes activity in the mortgage provision allowance:



	Three Months Ended March 31, 2017			Year Ended December 31, 2016
	Commercial mortgages			Commercial mortgages
Beginning balance	$	2,882		$	2,890
Provision increases	—			536
Provision decreases	(1,573		)	(544		)
Ending balance	$	1,309		$	2,882

Allowance ending balance by basis of impairment method:
Individually evaluated for impairment	$	536		$	536
Collectively evaluated for impairment	773			2,346

Recorded investment balance in the mortgage loan portfolio, gross of allowance, by basis of impairment method:	$	3,846,240		$	3,561,708
Individually evaluated for impairment	1,465			1,465
Collectively evaluated for impairment	3,844,775			3,560,243

Collateral received for securities loaned

The following table summarizes the cash collateral liability under the securities lending program, by class of securities loaned:



	March 31, 2017		December 31, 2016
Cash collateral liability by class of loaned security
U.S. government direct obligations and U.S. agencies	$	1,025	$	—
Corporate debt securities	93,506		—
Total	$	94,531	$	—

Schedule of unrealized investment losses, including the non-credit-related portion of OTTI losses reported in AOCI, by class of investment

The following tables summarize unrealized investment losses, including the non-credit-related portion of OTTI losses reported in AOCI, by class of investment:



	March 31, 2017
	Less than twelve months				Twelve months or longer				Total
	Estimated		Unrealized		Estimated		Unrealized		Estimated		Unrealized
Fixed maturities:	fair value		loss and OTTI		fair value		loss and OTTI		fair value		loss and OTTI
U.S. government direct obligations and U.S. agencies	$	1,254,124	$	18,974	$	10,181	$	215	$	1,264,305	$	19,189
Obligations of U.S. states and their subdivisions	165,820		4,641		10,394		480		176,214		5,121
Corporate debt securities	3,711,201		121,580		880,097		107,862		4,591,298		229,442
Asset-backed securities	458,552		4,905		271,982		11,766		730,534		16,671
Residential mortgage-backed securities	5,755		18		13,386		978		19,141		996
Commercial mortgage-backed securities	630,766		16,473		35,929		2,363		666,695		18,836
Collateralized debt obligations	30,980		36		—		—		30,980		36
Total fixed maturities	$	6,257,198	$	166,627	$	1,221,969	$	123,664	$	7,479,167	$	290,291

Total number of securities in an unrealized loss position			554				132				686



	December 31, 2016
	Less than twelve months				Twelve months or longer				Total
	Estimated		Unrealized		Estimated		Unrealized		Estimated		Unrealized
Fixed maturities:	fair value		loss and OTTI		fair value		loss and OTTI		fair value		loss and OTTI
U.S. government direct obligations and U.S. agencies	$	2,006,588	$	34,752	$	10,526	$	206	$	2,017,114	$	34,958
Obligations of U.S. states and their subdivisions	216,154		5,922		10,498		395		226,652		6,317
Corporate debt securities	4,119,630		170,453		860,153		138,711		4,979,783		309,164
Asset-backed securities	316,065		6,971		230,331		11,417		546,396		18,388
Residential mortgage-backed securities	16,962		102		14,297		1,065		31,259		1,167
Commercial mortgage-backed securities	592,508		17,535		26,068		2,647		618,576		20,182
Collateralized debt obligations	160,612		53		—		—		160,612		53
Total fixed maturities	$	7,428,519	$	235,788	$	1,151,873	$	154,441	$	8,580,392	$	390,229

Total number of securities in an unrealized loss position			610				128				738

Other-than-temporary impairment recognition

The OTTI on fixed maturity securities where the loss portion is bifurcated and the credit related component is recognized in realized investment gains (losses) is summarized as follows:



	Three Months Ended March 31,
	2017			2016
Beginning balance	$	83,665		$	102,343
Reductions due to increases in cash flows expected to be collected that are recognized over the remaining life of the security	(3,306		)	(3,927		)
Ending balance	$	80,359		$	98,416