Note 3. Investments in fixed maturity securities

Investments in fixed maturity securities as of March 31, 2019 and December 31, 2018 are summarized by type below (in millions).


	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
March 31, 2019
U.S. Treasury, U.S. government corporations and agencies	$	3,901	$	29	$	(12	)	$	3,918
States, municipalities and political subdivisions		145		6		—			151
Foreign governments		8,047		60		(16	)		8,091
Corporate bonds		6,259		470		(5	)		6,724
Mortgage-backed securities		470		63		(2	)		531

	$	18,822	$	628	$	(35	)	$	19,415

December 31, 2018
U.S. Treasury, U.S. government corporations and agencies	$	4,223	$	22	$	(22	)	$	4,223
States, municipalities and political subdivisions		182		7		—			189
Foreign governments		7,480		50		(28	)		7,502
Corporate bonds		7,055		408		(23	)		7,440
Mortgage-backed securities		487		59		(2	)		544

	$	19,427	$	546	$	(75	)	$	19,898

Investments in foreign governments include securities issued by national and provincial government entities as well as instruments that are unconditionally guaranteed by such entities. As of March 31, 2019, approximately 88% of our foreign government holdings were rated AA or higher by at least one of the major rating agencies.

The amortized cost and estimated fair value of fixed maturity securities at March 31, 2019 are summarized below by contractual maturity dates. Amounts are in millions. Actual maturities may differ from contractual maturities due to early call or prepayment rights held by issuers.


	Due in one year or less		Due after one year through five years		Due after five years through ten years		Due after ten years		Mortgage-backed securities		Total
Amortized cost	$	7,198	$	10,331	$	364	$	459	$	470	$	18,822
Fair value		7,242		10,443		410		789		531		19,415