Consolidated Statements of Comprehensive Income (unaudited) (Parenthetical) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Unrealized gains/(losses) arising during the period, tax expense/(benefit)	$ 0	$ (0.5)	$ (0.5)	$ (0.1)
Reclassification adjustments for losses included in net income, tax benefit	1.9	2.0	6.6	6.8
Amortization of net actuarial losses, tax benefit	$ 0.3	$ 0.4	$ 0.5	$ 1.4