Retirement and Postretirement Plans (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Information for the Non-qualified Plan, which had accumulated benefit obligations in excess of plan assets
Projected benefit obligation		$ 26.5	$ 27.5
Accumulated benefit obligation		26.5	27.5
Information for the Qualified Plan, which had accumulated benefit obligations less than plan assets
Projected benefit obligation		86.5	82.7
Accumulated benefit obligation		86.5	82.7
Fair value of plan net assets		120.8	133.0
Amounts recognized in accumulated other comprehensive income (loss) on a pre-tax basis noncontrolling interest
Accumulated other comprehensive income (loss) beginning balance	(16.7)	0.5	(8.5)
Increase (decrease) in accumulated other comprehensive income (loss):
Amortization of net actuarial losses recognized during the year		0.5	0.6
Net actuarial (losses) gains occurring during the year		(18.2)	8.4
Other adjustments		0.5
Accumulated other comprehensive (loss) income ending balance		(16.7)	0.5
Amount expected to be amortized from accumulated other comprehensive income (loss) into net periodic benefit cost during 2012	$ 0.7

The pretax total of net gain (loss), prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

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The aggregate amount in accumulated other comprehensive income expected to be recognized as a component of net periodic benefit cost over the fiscal year that follows the most recent annual statement of financial position presented, including the net gain (loss), net prior service cost or credit, and net transition asset or obligation.

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Pretax change in the value of either the benefit obligation or the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption, or the consequence of a decision to temporarily deviate from the substantive plan, that has not been recognized in net periodic benefit cost.

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