Accumulated Other Comprehensive Income (Loss) (Reconciliation Of The Components Of Accumulated Other Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Investments, Gross unrealized gains	$ 1,054.2	$ 1,282.1
Investments, Gross unrealized losses	(277.8)	(51.3)
Investments, Net pretax unrealized gains	776.4	1,230.8
Investments, Deferred tax liability	(267.4)	(427.1)
Net unrealized gains on investments	509.0	803.7
Non-credit components of OTTI on investments, Unrealized losses	(0.8)	(3.4)
Non-credit components of OTTI on investments, Deferred tax asset	0.3	1.2
Net unrealized non-credit component of OTTI on investments	(0.5)	(2.2)
Cash flow hedges, Gross unrealized losses	(49.7)	(54.3)
Cash flow hedges, Deferred tax asset	17.4	19.0
Net unrealized losses on cash flow hedges	(32.3)	(35.3)
Defined benefit pension plans, Deferred net actuarial loss	(427.2)	(686.8)
Defined benefit pension plans, Deferred prior service credits	3.0	3.9
Defined benefit pension plans, Deferred tax asset	169.9	269.1
Net unrecognized periodic benefit costs for defined benefit pension plans	(254.3)	(413.8)
Deferred Net Actuarial Loss Postretirement Benefits	(169.6)	(191.0)
Deferred Prior Service Credit Postretirement Benefit Plans	102.4	103.0
Postretirement benefit plans, Deferred tax asset	27.0	34.6
Net unrecognized periodic benefit costs for postretirement benefit plans	(40.2)	(53.4)
Foreign currency translation adjustments, Gross unrealized losses	2.2	0.2
Foreign currency translation adjustments, Deferred tax asset	(0.7)	(0.1)
Net unrealized losses on foreign currency translation adjustment	1.5	0.1
Accumulated other comprehensive income	$ 183.2	$ 299.1