Financing Receivables (Credit Quality Information Tables) (Details 3) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 3,571	$ 3,944
Less: allowance for loan losses	31	32	$ 34	$ 35
Commercial Real Estate Portfolio Segment [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	2,713	2,755
Less: allowance for loan losses	21	21
Total loans, net	$ 2,692	$ 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	$ 503	$ 504
Percentage of gross commercial mortgage loans	19.00%	18.00%
Commercial Real Estate Portfolio Segment [Member] | Hotel [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 34	$ 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	$ 440	$ 459
Percentage of gross commercial mortgage loans	16.00%	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	$ 513	$ 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	$ 972	$ 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	$ 214	$ 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	$ 201	$ 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	$ 77	$ 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	$ 207	$ 210
Percentage of gross commercial mortgage loans	8.00%	8.00%
Commercial Real Estate Portfolio Segment [Member] | Mountain [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 258	$ 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	$ 109	$ 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	$ 734	$ 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	$ 773	$ 782
Percentage of gross commercial mortgage loans	28.00%	28.00%
Commercial Real Estate Portfolio Segment [Member] | West North Central [Member]
Mortgage Loans on Real Estate [Line Items]
Financing Receivable, Gross	$ 219	$ 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	$ 135	$ 137
Percentage of gross commercial mortgage loans	5.00%	5.00%