Financing Receivables (Credit Quality Information Tables) (Details 2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	$ 3,911	$ 3,993
Less: allowance for loan losses	34	35	34	37
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of commercial mortgage loans with highest risk rating	1.00%	1.00%
Total loans, gross	2,683	2,729
Less: allowance for loan losses	23	25
Total loans, net	2,660	2,704
Percentage of gross commercial mortgage loans	100.00%	100.00%
Commercial Real Estate Portfolio Segment [Member] | Apartment Building [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	501	500
Percentage of gross commercial mortgage loans	19.00%	18.00%
Commercial Real Estate Portfolio Segment [Member] | Hotel [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	33	34
Percentage of gross commercial mortgage loans	1.00%	1.00%
Commercial Real Estate Portfolio Segment [Member] | Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	451	461
Percentage of gross commercial mortgage loans	17.00%	17.00%
Commercial Real Estate Portfolio Segment [Member] | Mixed use [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	45	45
Percentage of gross commercial mortgage loans	2.00%	2.00%
Commercial Real Estate Portfolio Segment [Member] | Office [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	527	545
Percentage of gross commercial mortgage loans	19.00%	20.00%
Commercial Real Estate Portfolio Segment [Member] | Retail [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	965	988
Percentage of gross commercial mortgage loans	36.00%	36.00%
Commercial Real Estate Portfolio Segment [Member] | Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	161	156
Percentage of gross commercial mortgage loans	6.00%	6.00%
Commercial Real Estate Portfolio Segment [Member] | East North Central [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	208	238
Percentage of gross commercial mortgage loans	8.00%	9.00%
Commercial Real Estate Portfolio Segment [Member] | East South Central [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	55	62
Percentage of gross commercial mortgage loans	2.00%	2.00%
Commercial Real Estate Portfolio Segment [Member] | Middle Atlantic [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	208	217
Percentage of gross commercial mortgage loans	8.00%	8.00%
Commercial Real Estate Portfolio Segment [Member] | Mountain [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	253	245
Percentage of gross commercial mortgage loans	9.00%	9.00%
Commercial Real Estate Portfolio Segment [Member] | New England [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	139	140
Percentage of gross commercial mortgage loans	5.00%	5.00%
Commercial Real Estate Portfolio Segment [Member] | Pacific [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	693	694
Percentage of gross commercial mortgage loans	26.00%	25.00%
Commercial Real Estate Portfolio Segment [Member] | South Atlantic [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	731	740
Percentage of gross commercial mortgage loans	27.00%	27.00%
Commercial Real Estate Portfolio Segment [Member] | West North Central [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	238	233
Percentage of gross commercial mortgage loans	9.00%	9.00%
Commercial Real Estate Portfolio Segment [Member] | West South Central [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans, gross	$ 158	$ 160
Percentage of gross commercial mortgage loans	6.00%	6.00%