Financing Receivables (Credit Quality Information Tables) (Details 3) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Commercial mortgage loans
Total loans, gross	$ 3,492	$ 3,944
Less: allowance for loan losses	29	32	$ 35	$ 37
Commercial mortgage loans [Member]
Commercial mortgage loans
Total loans, gross	2,702	2,755
Less: allowance for loan losses	21	21
Total loans, net	$ 2,681	$ 2,734
Percentage of gross commercial mortgage loans	100.00%	100.00%
Commercial mortgage loans [Member] | Apartments [Member]
Commercial mortgage loans
Total loans, gross	$ 504	$ 504
Percentage of gross commercial mortgage loans	19.00%	18.00%
Commercial mortgage loans [Member] | Hotel [Member]
Commercial mortgage loans
Total loans, gross	$ 42	$ 35
Percentage of gross commercial mortgage loans	1.00%	1.00%
Commercial mortgage loans [Member] | Industrial [Member]
Commercial mortgage loans
Total loans, gross	$ 446	$ 459
Percentage of gross commercial mortgage loans	17.00%	17.00%
Commercial mortgage loans [Member] | Mixed Use [Member]
Commercial mortgage loans
Total loans, gross	$ 49	$ 35
Percentage of gross commercial mortgage loans	2.00%	1.00%
Commercial mortgage loans [Member] | Office
Commercial mortgage loans
Total loans, gross	$ 489	$ 541
Percentage of gross commercial mortgage loans	18.00%	20.00%
Commercial mortgage loans [Member] | Retail
Commercial mortgage loans
Total loans, gross	$ 950	$ 984
Percentage of gross commercial mortgage loans	35.00%	36.00%
Commercial mortgage loans [Member] | Other
Commercial mortgage loans
Total loans, gross	$ 222	$ 197
Percentage of gross commercial mortgage loans	8.00%	7.00%
Commercial mortgage loans [Member] | East North Central [Member]
Commercial mortgage loans
Total loans, gross	$ 198	$ 211
Percentage of gross commercial mortgage loans	7.00%	8.00%
Commercial mortgage loans [Member] | East South Central [Member]
Commercial mortgage loans
Total loans, gross	$ 88	$ 74
Percentage of gross commercial mortgage loans	3.00%	3.00%
Commercial mortgage loans [Member] | Middle Atlantic [Member]
Commercial mortgage loans
Total loans, gross	$ 203	$ 210
Percentage of gross commercial mortgage loans	8.00%	8.00%
Commercial mortgage loans [Member] | Mountain [Member]
Commercial mortgage loans
Total loans, gross	$ 240	$ 248
Percentage of gross commercial mortgage loans	9.00%	9.00%
Commercial mortgage loans [Member] | New England [Member]
Commercial mortgage loans
Total loans, gross	$ 91	$ 123
Percentage of gross commercial mortgage loans	3.00%	4.00%
Commercial mortgage loans [Member] | Pacific [Member]
Commercial mortgage loans
Total loans, gross	$ 746	$ 741
Percentage of gross commercial mortgage loans	28.00%	27.00%
Commercial mortgage loans [Member] | South Atlantic [Member]
Commercial mortgage loans
Total loans, gross	$ 783	$ 782
Percentage of gross commercial mortgage loans	29.00%	28.00%
Commercial mortgage loans [Member] | West North Central [Member]
Commercial mortgage loans
Total loans, gross	$ 222	$ 229
Percentage of gross commercial mortgage loans	8.00%	8.00%
Commercial mortgage loans [Member] | West South Central [Member]
Commercial mortgage loans
Total loans, gross	$ 131	$ 137
Percentage of gross commercial mortgage loans	5.00%	5.00%