Investments (Details 3) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014 Holdings	Dec. 31, 2013 Holdings
Indemnity
Fair value
Less than 12 months	$ 54	$ 129
12 months or longer	21	26
Total	75	155
Unrealized losses
Less than 12 months	0	3
12 months or longer	1	0
Total	1	3
No. of holdings	19	38
Indemnity | Investment grade
Fair value
Less than 12 months	51	112
12 months or longer	0	10
Total	51	122
Unrealized losses
Less than 12 months	0	1
12 months or longer	0	0
Total	0	1
No. of holdings	14	32
Indemnity | Non-investment grade
Fair value
Less than 12 months	0	0
12 months or longer	0	0
Total	0	0
Unrealized losses
Less than 12 months	0	0
12 months or longer	0	0
Total	0	0
No. of holdings	0	0
Indemnity | Fixed maturities
Fair value
Less than 12 months	51	112
12 months or longer	0	10
Total	51	122
Unrealized losses
Less than 12 months	0	1
12 months or longer	0	0
Total	0	1
No. of holdings	14	32
Indemnity | States & political subdivisions
Fair value
Less than 12 months	11	58
12 months or longer	0	0
Total	11	58
Unrealized losses
Less than 12 months	0	1
12 months or longer	0	0
Total	0	1
No. of holdings	5	21
Indemnity | Corporate debt securities
Fair value
Less than 12 months	40	54
12 months or longer	0	10
Total	40	64
Unrealized losses
Less than 12 months	0	0
12 months or longer	0	0
Total	0	0
No. of holdings	9	11
Indemnity | Nonredeemable preferred stock
Fair value
Less than 12 months	3	5
12 months or longer	1	3
Total	4	8
Unrealized losses
Less than 12 months	0	1
12 months or longer	0	0
Total	0	1
No. of holdings	3	4
Indemnity | Common stock
Fair value
Less than 12 months	0	12
12 months or longer	20	13
Total	20	25
Unrealized losses
Less than 12 months	0	1
12 months or longer	1	0
Total	1	1
No. of holdings	2	2
Exchange
Fair value
Less than 12 months	1,252	2,050
12 months or longer	201	176
Total	1,453	2,226
Unrealized losses
Less than 12 months	28	74
12 months or longer	7	5
Total	35	79
No. of holdings	265	388
Exchange | Investment grade
Fair value
Less than 12 months	1,104	1,707
12 months or longer	81	62
Total	1,185	1,769
Unrealized losses
Less than 12 months	23	57
12 months or longer	4	4
Total	27	61
No. of holdings	238	344
Exchange | Non-investment grade
Fair value
Less than 12 months	32	64
12 months or longer	5	0
Total	37	64
Unrealized losses
Less than 12 months	1	4
12 months or longer	1	0
Total	2	4
No. of holdings	8	14
Exchange | Fixed maturities
Fair value
Less than 12 months	1,136	1,771
12 months or longer	86	62
Total	1,222	1,833
Unrealized losses
Less than 12 months	24	61
12 months or longer	5	4
Total	29	65
No. of holdings	246	358
Exchange | U.S. government & agencies
Fair value
Less than 12 months		1
12 months or longer		0
Total		1
Unrealized losses
Less than 12 months		0
12 months or longer		0
Total		0
No. of holdings		2
Exchange | U.S. treasury
Fair value
Less than 12 months	3
12 months or longer	0
Total	3
Unrealized losses
Less than 12 months	0
12 months or longer	0
Total	0
No. of holdings	3
Exchange | States & political subdivisions
Fair value
Less than 12 months	216	408
12 months or longer	31	18
Total	247	426
Unrealized losses
Less than 12 months	5	13
12 months or longer	2	2
Total	7	15
No. of holdings	62	100
Exchange | Foreign government securities
Fair value
Less than 12 months	0	5
12 months or longer	5	0
Total	5	5
Unrealized losses
Less than 12 months	0	0
12 months or longer	0	0
Total	0	0
No. of holdings	1	1
Exchange | Corporate debt securities
Fair value
Less than 12 months	828	1,251
12 months or longer	36	36
Total	864	1,287
Unrealized losses
Less than 12 months	17	43
12 months or longer	2	2
Total	19	45
No. of holdings	161	237
Exchange | Residential mortgage-backed securities
Fair value
Less than 12 months	67	71
12 months or longer	14	8
Total	81	79
Unrealized losses
Less than 12 months	2	4
12 months or longer	1	0
Total	3	4
No. of holdings	14	12
Exchange | Commercial mortgage-backed securities
Fair value
Less than 12 months	2	5
12 months or longer	0	0
Total	2	5
Unrealized losses
Less than 12 months	0	0
12 months or longer	0	0
Total	0	0
No. of holdings	1	1
Exchange | Other debt securities
Fair value
Less than 12 months	20	30
12 months or longer	0	0
Total	20	30
Unrealized losses
Less than 12 months	0	1
12 months or longer	0	0
Total	0	1
No. of holdings	4	5
Exchange | Nonredeemable preferred stock
Fair value
Less than 12 months	85	182
12 months or longer	15	13
Total	100	195
Unrealized losses
Less than 12 months	3	10
12 months or longer	1	1
Total	4	11
No. of holdings	17	27
Exchange | Common stock
Fair value
Less than 12 months	31	97
12 months or longer	100	101
Total	131	198
Unrealized losses
Less than 12 months	1	3
12 months or longer	1	0
Total	$ 2	$ 3
No. of holdings	2	3