Employee Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012 Age	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined contribution plans, expense under plans	$ 16.4	$ 16.8	$ 17.5
Deferred compensation plans, liability under plans	49.6	47.0
Deferred compensation plans, expense under plans	4.2	0.7	4.5
Benefit determination period for pension plan	5 years
Defined benefit plan, non-contributory, retirement age requirement	62
Defined benefit plan, contributory, retirement age requirement	62
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer contributions in next fiscal year	1.6
Postretirement health and life plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected employer contributions in next fiscal year	$ 0.9
Minimum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, contributory, employee contribution percentage	25.00%
Maximum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined benefit plan, contributory, employee contribution percentage	100.00%