Investments (Tables)

6 Months Ended

Jun. 30, 2018

Amortized cost and fair value of investments in fixed maturities [Table Text Block]

The amortized cost and fair value of investments in fixed maturities classified as available for sale were as follows:



	Amortized		Gross Unrealized				Fair
(at June 30, 2018, in millions)	Cost		Gains		Losses		Value
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,041	$	1	$	23	$	2,019
Obligations of states, municipalities and political subdivisions:
Local general obligation	13,992		201		136		14,057
Revenue	9,857		171		88		9,940
State general obligation	1,384		19		12		1,391
Pre-refunded	3,432		111		1		3,542
Total obligations of states, municipalities and political subdivisions	28,665		502		237		28,930
Debt securities issued by foreign governments	1,281		8		8		1,281
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	2,499		66		49		2,516
All other corporate bonds	28,102		161		563		27,700
Redeemable preferred stock	86		4		—		90
Total	$	62,674	$	742	$	880	$	62,536



	Amortized		Gross Unrealized				Fair
(at December 31, 2017, in millions)	Cost		Gains		Losses		Value
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	2,080	$	4	$	8	$	2,076
Obligations of states, municipalities and political subdivisions:
Local general obligation	13,488		444		26		13,906
Revenue	11,307		338		19		11,626
State general obligation	1,443		44		3		1,484
Pre-refunded	3,758		142		1		3,899
Total obligations of states, municipalities and political subdivisions	29,996		968		49		30,915
Debt securities issued by foreign governments	1,505		14		10		1,509
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	2,334		87		11		2,410
All other corporate bonds	25,311		478		100		25,689
Redeemable preferred stock	90		5		—		95
Total	$	61,316	$	1,556	$	178	$	62,694

Cost and fair value of investments in equity securities [Table Text Block]



							Fair
(at June 30, 2018, in millions)	Cost		Gross Gains		Gross Losses		Value
Public common stock	$	335	$	12	$	5	$	342
Non-redeemable preferred stock	74		11		3		82
Total	$	409	$	23	$	8	$	424

Cost and fair value of investments in equity securities classified as available for sale [Table Text Block]



							Fair
(at December 31, 2017, in millions)	Cost		Gross Gains		Gross Losses		Value
Public common stock	$	332	$	8	$	1	$	339
Non-redeemable preferred stock	108		12		6		114
Total	$	440	$	20	$	7	$	453

Unrealized investment losses [Table Text Block]

The following tables summarize, for all investments in an unrealized loss position at June 30, 2018 and December 31, 2017, the aggregate fair value and gross unrealized loss by length of time those securities have been continuously in an unrealized loss position. The fair value amounts reported in the tables are estimates that are prepared using the process described in note 4 herein and in note 4 of notes to the consolidated financial statements in the Company’s 2017 Annual Report. The Company also relies upon estimates of several factors in its review and evaluation of individual investments, using the process described in note 1 of notes to the consolidated financial statements in the Company’s 2017 Annual Report in determining whether such investments are other-than-temporarily impaired.



	Less than 12 months				12 months or longer				Total
(at June 30, 2018, in millions)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	1,410	$	20	$	458	$	3	$	1,868	$	23
Obligations of states, municipalities and political subdivisions	6,321		101		2,856		136		9,177		237
Debt securities issued by foreign governments	206		2		241		6		447		8
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,557		41		256		8		1,813		49
All other corporate bonds	17,584		441		2,313		122		19,897		563
Total fixed maturities	$	27,078	$	605	$	6,124	$	275	$	33,202	$	880



	Less than 12 months				12 months or longer				Total
(at December 31, 2017, in millions)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Fixed maturities
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities	$	1,150	$	5	$	470	$	3	$	1,620	$	8
Obligations of states, municipalities and political subdivisions	505		2		2,959		47		3,464		49
Debt securities issued by foreign governments	394		6		111		4		505		10
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities	1,021		7		250		4		1,271		11
All other corporate bonds	6,062		48		1,990		52		8,052		100
Total fixed maturities	9,132		68		5,780		110		14,912		178
Equity securities
Public common stock	18		—		34		1		52		1
Non-redeemable preferred stock	3		—		56		6		59		6
Total equity securities	21		—		90		7		111		7
Total	$	9,153	$	68	$	5,870	$	117	$	15,023	$	185