Investments (Rating info) (Details) (USD $)	Jun. 30, 2014 item	Dec. 31, 2013
Investments
Amortized Cost	$ 22,046,000,000	$ 22,904,000,000
Fair Value	24,183,000,000	24,393,000,000
Percentage of GNMA, FNMA and FHLMC securities rated AAA	44.00%	41.00%
Number of holdings of other than GNMA, FNMA and FHLMC having greater than 10% of total equity	0
AAA
Investments
Amortized Cost	5,384,000,000	5,557,000,000
Fair Value	5,649,000,000	5,738,000,000
Percent of Total Fair Value	23.00%	23.00%
AA
Investments
Amortized Cost	986,000,000	1,055,000,000
Fair Value	1,158,000,000	1,171,000,000
Percent of Total Fair Value	5.00%	5.00%
A
Investments
Amortized Cost	4,513,000,000	4,687,000,000
Fair Value	5,049,000,000	5,062,000,000
Percent of Total Fair Value	21.00%	21.00%
BBB
Investments
Amortized Cost	9,659,000,000	10,062,000,000
Fair Value	10,799,000,000	10,897,000,000
Percent of Total Fair Value	45.00%	45.00%
Below investment grade
Investments
Amortized Cost	1,502,000,000	1,541,000,000
Fair Value	1,520,000,000	1,519,000,000
Percent of Total Fair Value	6.00%	6.00%
Total fixed maturities
Investments
Fixed maturity securities as percentage of the entity's total investments	83.00%	83.00%
Amount of securities internally rated	1,200,000,000	1,300,000,000
Amortized Cost	22,044,000,000	22,902,000,000
Fair Value	$ 24,175,000,000	$ 24,387,000,000
Percent of Total Fair Value	100.00%	100.00%