Accumulated Other Comprehensive Income: Accumulated Other Comprehensive Income (Reclassifications) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Total reclassification for the period, net of tax	$ 1.1	[1]	$ (4.4)
Plan Curtailment
Pension and postretirement plans	0	[2]	(9.5)	[2]
Amortization of Net Actuarial Loss
Pension and postretirement plans	0.2	[2]	0	[2]
Amortization of Prior Service Credits
Pension and postretirement plans	(1.3)	[2]	(1.7)	[2]
Pension and Postretirement Plans
Total reclassification for the period, net of tax	(0.9)		(7.0)
Interest Rate Swap
Total reclassification for the period, net of tax	2.0		2.6
Interest Expense | Interest Rate Swap
Amortization of unrealized losses on de-designated interest rate swaps	3.4		4.2
Income from Continuing Operations Before Income Taxes | Pension and Postretirement Plans
Pension and postretirement plans	(1.1)		(11.2)
Income from Continuing Operations Before Income Taxes | Interest Rate Swap
Amortization of unrealized losses on de-designated interest rate swaps	3.4		4.2
Income Taxes | Pension and Postretirement Plans
Other comprehensive income, tax effect	0.2		4.2
Income Taxes | Interest Rate Swap
Other comprehensive income, tax effect	$ (1.4)		$ (1.6)

[1] See separate table below for details about these reclassifications.

[2] These accumulated other comprehensive income components are included in the computation of net periodic benefit income. See Note 7 for additional details.