Income Taxes (Reconciliation of Income Tax Provision) (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of the income tax provision
Tax at U.S. statutory rate (as a percent)	21.00%	35.00%	35.00%
Changes in taxes resulting from:
Low income housing tax credit (as a percent)	(3.20%)	(3.40%)	(4.20%)
Dividend received deduction (as a percent)	(1.60%)	(5.80%)	(7.60%)
State taxes, net of federal benefit (as a percent)	1.50%	0.00%	1.90%
Foreign tax credits, net of addback (as a percent)	(1.10%)	0.00%	(1.60%)
Impact of the Tax Act (as a percent)	0.00%	13.00%
Incentive compensation (as a percent)	0.00%	(3.00%)
Foreign taxes (as a percent)	0.00%	(2.00%)	(2.50%)
Taxes applicable to prior years (as a percent)	0.00%	0.00%	(3.10%)
Other, net (as a percent)	(1.10%)	(0.70%)	(0.50%)
Income tax provision (as a percent)	15.50%	33.10%	17.40%
Expense related to the enactment of the Tax Act		$ 286
Net excess tax benefit recognized in income tax provisions	$ 70	$ 70
Accumulated Earnings of Foreign Subsidiaries	$ 13