Income Taxes (Reconciliation of Income Tax Provision) (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Benefits Tax Planning and Completion of Audits	$ 17,000,000
Decrease to Tax Expense from Out of Period Correction for Deferred Tax Balance			16,000,000
Increase to Tax Expense from Out of Period Correction for Tax Item Related to Securities Lending Activity			32,000,000
Reconciliation of the income tax provision
Tax at U.S. statutory rate (as a percent)	35.00%	35.00%	35.00%
Changes in taxes resulting from:
Net income (loss) attributable to noncontrolling interests (as a percent)	(5.20%)	(2.50%)	3.60%
Dividend exclusion (as a percent)	(4.70%)	(5.10%)	(5.90%)
Low income housing tax credit (as a percent)	(2.10%)	(2.70%)	(3.00%)
Foreign tax credits, net of addback (as a percent)	(2.00%)	(0.90%)	(3.20%)
State taxes, net of federal benefit (as a percent)	1.60%	0.50%	2.50%
Tax-exempt interest income (as a percent)	(0.70%)	(0.90%)	(1.70%)
Taxes applicable to prior years (as a percent)	(0.20%)	0.00%	(2.50%)
Other, net (as a percent)	(0.30%)	1.60%	2.30%
Income tax provision (as a percent)	21.40%	25.00%	27.10%
Accumulated earnings of foreign subsidiaries	180,000,000
Aggregate U.S. federal taxes not provided on earnings of foreign subsidiaries	$ 40,000,000