Employee Benefit Arrangements (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	3 Months Ended		9 Months Ended
	Aug. 16, 2012 employee	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net Periodic Benefit Costs [Abstract]
Earned benefit by participants, as percentage of eligible compensation				4.00%
Number of employees transitioned to service provider (more than)	1,000
Net loss before income taxes recognized on plan revaluation		$ 0	$ 108.4	$ 0	$ 108.4
Company match percentage of participant's eligible compensation				6.00%
Award vesting period				4 years
Pension Plans
Net Periodic Benefit Costs [Abstract]
Service cost		11.4	10.2	34.0	29.6
Interest cost		22.0	22.6	66.2	67.7
Expected return on plan assets		(25.3)	(23.3)	(75.9)	(68.4)
Amortization of prior service cost (credit)		(2.6)	(2.8)	(7.8)	(8.5)
(Gain) loss recognized due to curtailments		0	(6.9)	0	(6.9)
Net loss (gain) recognition		0	115.2	0	115.2
Net periodic (benefit) costs		5.5	115.0	16.5	128.7
Net loss before income taxes recognized on plan revaluation					108.3
Other Postretirement Benefits
Net Periodic Benefit Costs [Abstract]
Service cost		0	0	0	0
Interest cost		(0.7)	0.4	0.1	1.1
Expected return on plan assets		0	0	0	0
Amortization of prior service cost (credit)		(0.8)	(0.8)	(2.5)	(2.5)
(Gain) loss recognized due to curtailments		0	0	0	0
Net loss (gain) recognition		0	0.1	0	0.1
Net periodic (benefit) costs		$ (1.5)	$ (0.3)	$ (2.4)	$ (1.3)