Investments (Details 4) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Investment income from portfolios
Investment income, net of expenses	$ 111	$ 104	$ 220	$ 207
Indemnity
Investment income from portfolios
Total investment income	4	4	8	8
Less: investment expenses	0	1	0	1
Investment income, net of expenses	4	3	8	7
Indemnity | Fixed maturities
Investment income from portfolios
Total investment income	3	3	6	6
Indemnity | Equity securities
Investment income from portfolios
Total investment income	0	0	1	1
Indemnity | Cash equivalents and other
Investment income from portfolios
Total investment income	1	1	1	1
Exchange
Investment income from portfolios
Total investment income	116	110	231	217
Less: investment expenses	9	9	19	17
Investment income, net of expenses	107	101	212	200
Exchange | Fixed maturities
Investment income from portfolios
Total investment income	85	83	171	166
Exchange | Equity securities
Investment income from portfolios
Total investment income	30	27	59	51
Exchange | Cash equivalents and other
Investment income from portfolios
Total investment income	$ 1	$ 0	$ 1	$ 0