Income Taxes (Reconciliation Of Income Tax Expense Computed At The Statutory Federal Income Tax Rate) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Amount at statutory rate, amount	$ 1,528.8	$ 1,344.1	$ 1,350.4
Amount at statutory rate, percent	35.00%	35.00%	35.00%
State and local income taxes net of federal tax benefit, amount	49.0	24.4	25.5
State and local income taxes net of federal tax benefit, percent	1.10%	0.60%	0.60%
Tax exempt interest and dividends received deduction, amount	(65.9)	(64.9)	(59.3)
Tax exempt interest and dividends received deduction, percent	(1.50%)	(1.70%)	(1.50%)
Health Insurance Provider fee, amount	312.6	0	0
Health Insurance Provider fee, percent	7.20%	0.00%	0.00%
Audit settlements, amount	0	0	(200.5)
Audit settlements, percent	0.00%	0.00%	(5.20%)
Other, net amount	(16.5)	(97.7)	91.2
Other, net percent	(0.40%)	(2.50%)	2.40%
Total income tax expense	$ 1,808.0	$ 1,205.9	$ 1,207.3
Total income tax expense, percent	41.40%	31.40%	31.30%