Investments (Related Party Invesment Transactions - Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Commercial mortgage loans portfolio segment [Member]	Sep. 30, 2012 Commercial mortgage loans portfolio segment [Member]	Sep. 30, 2013 Commercial mortgage loans portfolio segment [Member]	Sep. 30, 2012 Commercial mortgage loans portfolio segment [Member]	Sep. 30, 2013 Other invested assets [Member]	Sep. 30, 2012 Other invested assets [Member]	Sep. 30, 2013 Other invested assets [Member]	Sep. 30, 2012 Other invested assets [Member]	Sep. 30, 2013 Affiliated Entity [Member] Commercial mortgage loans portfolio segment [Member]	Dec. 31, 2012 Affiliated Entity [Member] Commercial mortgage loans portfolio segment [Member]	Sep. 30, 2013 Affiliated Entity [Member] Other invested assets [Member]	Dec. 31, 2012 Affiliated Entity [Member] Other invested assets [Member]
Related Party Transaction [Line Items]
Related party investment administrative services	$ 17	$ 16	$ 51	$ 50
Carrying value of related party loans													304	306	430	430
Related party net investment income	$ 1	$ 1	$ (1)	$ 1	$ 4	$ 4	$ 12	$ 12	$ 6	$ 6	$ 18	$ 18