Employee Benefit Plans (Components Of Net Period Benefit Cost) (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Mark-to-market actuarial net losses (gains)	$ 11.6	$ 56.5	$ (44.0)	$ 11.6	$ 56.5
Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost				1.7	1.6	$ 1.7
Interest cost				21.3	24.9	23.9
Expected return on plan assets				(32.7)	(32.2)	(37.4)
Mark-to-market actuarial net losses (gains)				15.2	55.2	(43.0)
Net periodic benefit cost (gain)				5.5	49.5	(54.8)
Health Care Benefits
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost				0.0	0.0	0.0
Interest cost				0.6	0.7	0.6
Expected return on plan assets				0.0	0.0	0.0
Mark-to-market actuarial net losses (gains)				(3.6)	1.3	(1.0)
Net periodic benefit cost (gain)				$ (3.0)	$ 2.0	$ (0.4)