Consolidated Statement of Changes in Stockholders' Equity (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net change in unrealized gains on available-for-sale securities, net tax benefit	$ 0.0	$ 0.3	$ (0.1)	$ (0.8)
Net unrealized gains on cash flow hedges, net tax provision	81.0	37.2	79.8	106.1
Postretirement plans and workers' compensation obligations, net tax provision	$ 9.4	$ 4.0	$ 9.4	$ (2.2)