Investments Investments (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Investment income from portfolios
Investment income, net of expenses	$ 422	$ 438	$ 433
Indemnity
Investment income from portfolios
Total investment income	16	17	17
Less: investment expenses	1	1	1
Investment income, net of expenses	15	16	16
Indemnity | Fixed maturities
Investment income from portfolios
Total investment income	12	13	14
Indemnity | Equity securities
Investment income from portfolios
Total investment income	2	3	2
Indemnity | Cash equivalents and other
Investment income from portfolios
Total investment income	2	1	1
Exchange
Investment income from portfolios
Total investment income	441	454	450
Less: investment expenses	34	32	33
Investment income, net of expenses	407	422	417
Exchange | Fixed maturities
Investment income from portfolios
Total investment income	334	350	364
Exchange | Equity securities
Investment income from portfolios
Total investment income	105	102	86
Exchange | Cash equivalents and other
Investment income from portfolios
Total investment income	$ 2	$ 2	$ 0