Net Earnings Per Common Share - Calculation of Basic and Diluted Net Earnings (Loss) Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator
Net earnings available to common stockholders		$ 163.3	$ 86.6	$ 315.3	$ 211.9	[1]
Distributed and allocated undistributed net loss to non-vested restricted stockholders		(1.2)	(0.6)	(2.2)	(1.5)
Distributed and allocated undistributed net earnings to common stockholders		162.1	86.0	313.1	210.4
Distributed net earnings - dividends paid to common stockholders		(31.3)	(26.1)	(88.0)	(80.6)
Allocation of undistributed net earnings to common stockholders		$ 130.8	$ 59.9	$ 225.1	$ 129.8
Denominator
Weighted average number of common shares outstanding - basic		194.1	202.9	195.0	206.7
Basic net earnings per common share:
Distributed net earnings to common stockholders		$ 0.16	$ 0.13	$ 0.45	$ 0.39
Allocated undistributed net earnings to common stockholders		0.68	0.30	1.15	0.63
Basic net earnings per common share:	[2]	$ 0.84	$ 0.43	$ 1.60	$ 1.02
Numerator
Distributed and allocated undistributed net earnings to common stockholders		$ 162.1	$ 86.0	$ 313.1	$ 210.4
Add: Allocated undistributed net earnings to unvested restricted stockholders		1.1	0.5	1.7	1.0
Less: Undistributed net earnings (loss) reallocated to non-vested restricted stockholders		(1.1)	(0.5)	(1.7)	(1.0)
Net earnings available to common stockholders - diluted		$ 162.1	$ 86.0	$ 313.1	$ 210.4
Denominator
Weighted average number of common shares outstanding - basic		194.1	202.9	195.0	206.7
Effect of contingently issuable shares		1.0	1.4	0.9	1.3
Effect of unvested restricted stock units		0.9	0.7	0.9	0.7
Weighted average number of common shares outstanding - diluted under two-class		196.0	205.0	196.8	208.7
Effect of unvested restricted stock - participating security		0.7	0.8	0.7	0.8
Weighted average number of common shares outstanding - diluted under treasury stock	[2]	196.7	205.8	197.5	209.5
Diluted net earnings per common share	[2]	$ 0.83	$ 0.42	$ 1.59	$ 1.01

[1] For the nine months ended September 30, 2015, certain amounts related to the settlement of a net investment hedge and foreign currency gains and losses were misclassified. Additional revisions were made to the Condensed Consolidated Balance Sheet as of September 30, 2015. As a result, corresponding changes were made on the Condensed Consolidated Statement of Cash Flows. See Note 1 “Organization and Basis of Presentation” under the heading “Reclassifications and Revisions” for further discussion of the revisions.

[2] The Company early adopted ASU 2016-09 on a prospective basis as required, related to the recognition of excess tax benefits to the income statement which were previously recorded in additional paid-in capital, effective January 1, 2016. This resulted in an additional 377,130 and 370,090 diluted weighted average number of common shares outstanding for the three and nine months ended September 30, 2016, respectively, and recognition of excess tax benefits of $1.8 million and $12.4 million in income tax provision for the three and nine months ended September 30, 2016, respectively. As a result, net earnings per common share increased by $0.01 per share and $0.06 per share for the three and nine months ended September 30, 2016, respectively. Refer to Note 2, “Recently Issued Accounting Standards” of the notes to the condensed consolidated financial statements for further details.