Items Measured at Fair Value on a Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Millions		Jun. 30, 2016		Dec. 31, 2015
Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (Note 14)		$ 0.3		$ 0.6
Total assets		157.0		198.6
Derivative liabilities (Note 14)		7.7		14.8
Total liabilities		33.1		37.0
Bank time deposits with original maturities of three months or less | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Bank time deposits with original maturities of three months or less		131.6		176.0
Diversified investments associated with the Executive Stock Unit Program (ESUP) | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Diversified investments associated with the Executive Stock Unit Program (ESUP)		25.1	[1]	22.0
Liabilities Associated With Esup | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities	[1]	25.4		22.2
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (Note 14)		0.0		0.0
Total assets		25.1		22.0
Derivative liabilities (Note 14)		0.0		0.0
Total liabilities		25.4		22.2
Level 1 | Bank time deposits with original maturities of three months or less
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Bank time deposits with original maturities of three months or less		0.0		0.0
Level 1 | Diversified investments associated with the Executive Stock Unit Program (ESUP)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Diversified investments associated with the Executive Stock Unit Program (ESUP)		25.1	[1]	22.0
Level 1 | Liabilities Associated With Esup
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities	[1]	25.4		22.2
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (Note 14)		0.3		0.6
Total assets		131.9		176.6
Derivative liabilities (Note 14)		7.7		14.8
Total liabilities		7.7		14.8
Level 2 | Bank time deposits with original maturities of three months or less
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Bank time deposits with original maturities of three months or less		131.6		176.0
Level 2 | Diversified investments associated with the Executive Stock Unit Program (ESUP)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Diversified investments associated with the Executive Stock Unit Program (ESUP)		0.0	[1]	0.0
Level 2 | Liabilities Associated With Esup
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities	[1]	0.0		0.0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (Note 14)		0.0		0.0
Total assets		0.0		0.0
Derivative liabilities (Note 14)		0.0		0.0
Total liabilities		0.0		0.0
Level 3 | Bank time deposits with original maturities of three months or less
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Bank time deposits with original maturities of three months or less		0.0		0.0
Level 3 | Diversified investments associated with the Executive Stock Unit Program (ESUP)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Diversified investments associated with the Executive Stock Unit Program (ESUP)		0.0	[1]	0.0
Level 3 | Liabilities Associated With Esup
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities	[1]	$ 0.0		$ 0.0

[1] Includes both current and long-term amounts combined.