Financing Receivables (Credit Quality Information Tables) (Details 3) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 3,498	$ 3,944
Less: allowance for loan losses	30	32	$ 33	$ 35
Commercial Real Estate Portfolio Segment [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	2,682	2,755
Less: allowance for loan losses	21	21
Total loans, net	$ 2,661	$ 2,734
Percentage of gross commercial mortgage loans	100.00%	100.00%
Commercial Real Estate Portfolio Segment [Member] | Apartment Building [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 492	$ 504
Percentage of gross commercial mortgage loans	18.00%	18.00%
Commercial Real Estate Portfolio Segment [Member] | Hotel [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 43	$ 35
Percentage of gross commercial mortgage loans	1.00%	1.00%
Commercial Real Estate Portfolio Segment [Member] | Industrial [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 447	$ 459
Percentage of gross commercial mortgage loans	17.00%	17.00%
Commercial Real Estate Portfolio Segment [Member] | Mixed use [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 37	$ 35
Percentage of gross commercial mortgage loans	1.00%	1.00%
Commercial Real Estate Portfolio Segment [Member] | Office [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 496	$ 541
Percentage of gross commercial mortgage loans	19.00%	20.00%
Commercial Real Estate Portfolio Segment [Member] | Retail [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 961	$ 984
Percentage of gross commercial mortgage loans	36.00%	36.00%
Commercial Real Estate Portfolio Segment [Member] | Other [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 206	$ 197
Percentage of gross commercial mortgage loans	8.00%	7.00%
Commercial Real Estate Portfolio Segment [Member] | East North Central [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 202	$ 211
Percentage of gross commercial mortgage loans	7.00%	8.00%
Commercial Real Estate Portfolio Segment [Member] | East South Central [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 76	$ 74
Percentage of gross commercial mortgage loans	3.00%	3.00%
Commercial Real Estate Portfolio Segment [Member] | Middle Atlantic [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 199	$ 210
Percentage of gross commercial mortgage loans	7.00%	8.00%
Commercial Real Estate Portfolio Segment [Member] | Mountain [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 260	$ 248
Percentage of gross commercial mortgage loans	10.00%	9.00%
Commercial Real Estate Portfolio Segment [Member] | New England [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 100	$ 123
Percentage of gross commercial mortgage loans	4.00%	4.00%
Commercial Real Estate Portfolio Segment [Member] | Pacific [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 721	$ 741
Percentage of gross commercial mortgage loans	27.00%	27.00%
Commercial Real Estate Portfolio Segment [Member] | South Atlantic [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 770	$ 782
Percentage of gross commercial mortgage loans	29.00%	28.00%
Commercial Real Estate Portfolio Segment [Member] | West North Central [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 226	$ 229
Percentage of gross commercial mortgage loans	8.00%	8.00%
Commercial Real Estate Portfolio Segment [Member] | West South Central [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 128	$ 137
Percentage of gross commercial mortgage loans	5.00%	5.00%