Consolidated Statements of Comprehensive Income (unaudited) (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Unrealized gains/(losses) arising during the period, tax expense/(benefit)	$ (0.1)	$ (0.1)	$ 0.3	$ 0.4
Reclassification adjustments for losses included in net income, tax benefit	1.9	2.0	3.9	4.8
Amortization of net actuarial losses, tax benefit	$ 0.1	$ 0.5	$ 0.2	$ 1.0