Retirement and Postretirement Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Components of net periodic benefit cost
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements and Curtailments	$ 10.7
Pension [Member]
Components of net periodic benefit cost
Service cost	8.4	7.9	17.2	16.2
Interest cost	37.8	39.6	75.6	79.4
Expected return on plan assets	(55.3)	(57.5)	(110.5)	(107.6)
Amortization of prior service cost (credit)	2.4	2.3	4.7	4.7
Amortization of net actuarial loss	20.5	15.2	41.7	28.0
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements and Curtailments	10.7	0	10.7	0
Net periodic benefit cost	24.5	7.5	39.4	20.7
Postretirement Benefit Plans [Member]
Components of net periodic benefit cost
Service cost	0.5	0.7	1.2	1.2
Interest cost	6.7	7.5	13.9	16.2
Expected return on plan assets	(2.5)	(1.5)	(5.3)	(2.2)
Amortization of prior service cost (credit)	0	0.2	(0.1)	(0.2)
Amortization of net actuarial loss	0.2	0.5	1.3	1.5
Net periodic benefit cost	$ 4.9	$ 7.4	$ 11.0	$ 16.5