Changes In Equity And Comprehensive Income (Summary Of Changes In Equity) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period			$ 1,145.7	$ 1,150.8
Dividends			(58.8)	(57.8)
Treasury Stock, Value, Acquired, Cost Method			25.0	0.0
Exercise of stock options, net of shares reacquired			20.7	9.6
Stock compensation expense			16.5	16.8
Excess tax benefit from stock based compensation			0.0	0.1
Net income	$ 68.5	$ 63.7	201.1	187.3
Other comprehensive income (loss)	26.9	(3.4)	90.1	17.2
Comprehensive income	95.4	60.3	291.2	204.5
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	(1.4)	0.2	(0.7)	0.5
Balance, end of period	1,390.3	1,324.0	1,390.3	1,324.0
Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period			1,133.8	1,139.4
Dividends			(58.8)	(57.8)
Treasury Stock, Value, Acquired, Cost Method			25.0	0.0
Exercise of stock options, net of shares reacquired			20.7	9.6
Stock compensation expense			16.5	16.8
Excess tax benefit from stock based compensation			0.0	0.1
Net income			200.5	186.8
Other comprehensive income (loss)			91.4	17.2
Comprehensive income			291.9	204.0
Balance, end of period	1,379.1	1,312.1	1,379.1	1,312.1
Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance, beginning of period			11.9	11.4
Net income			0.6	0.5
Other comprehensive income (loss)			(1.3)	0.0
Comprehensive income				0.5
Balance, end of period	$ 11.2	$ 11.9	$ 11.2	$ 11.9