Consolidated Statement of Changes in Stockholders' Equity (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
Net change in unrealized holding losses on available-for-sale securities, tax benefit	$ 0.2	$ (1.8)	$ 1.0	$ (1.7)
Net unrealized gains on cash flow hedges, tax provision	(104.2)	6.7	1.9	(221.3)
Postretirement plans and workers' compensation obligations, tax provision	$ 4.0	$ 8.3	$ 1.8	$ 25.0