Fair Value of Pension Plan Assets (Detail) (U.S. Plan, USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	$ 1,440.8	$ 1,342.1	$ 1,277.7
COMMON STOCK | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	14.8
Preferred and Common Stock | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		116.0
Preferred and Common Stock | Non U.S.
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		56.8
Fixed Income | U.S. Government Sponsored Agency
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	159.5	131.7
Other Investment | Mutual Funds | Global Large Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	69.6
Other Investment | Mutual Funds | Foreign Large Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		66.6
Other Investment | Mutual Funds | Domestic Large Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		69.4
Other Investment | Collective Trust Fund | Foreign Large Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	105.4	74.3
Other Investment | Collective Trust Fund | Foreign Small Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	37.2	31.6
Other Investment | Collective Trust Fund | Domestic Large Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	196.7	101.0
Other Investment | Collective Trust Fund | Domestic Small Cap Value
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	26.5	26.3
Other Investment | Collective Trust Fund | Domestic Mid Cap Value
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	14.4	19.1
Other Investment | Collective Trust Fund | Domestic Small Cap Growth
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	21.2	14.3
Other Investment | Collective Trust Fund | Domestic Mid Cap Growth
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	15.2	38.0
Other Investment | Collective Trust Fund | Short-Term Investment
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	3.4	6.6
Other Investment | Collective Trust Fund | Global Real Estate Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	73.8	65.4
Other Investment | Collective Trust Fund | Domestic Long-Term Bond
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	508.0	333.7
Other Investment | Collective Trust Fund | Emerging Market Large Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	68.2	40.9
Other Investment | Commodity Linked Fund
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		39.7
Other Investment | Ishares Index Fund
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		2.4
Other Investment | Private Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	49.0	47.7
Other Investment | Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	68.6	55.1
Cash and Other
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	9.3	5.5
Fair Value, Inputs, Level 1
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	93.7	352.5
Fair Value, Inputs, Level 1 | COMMON STOCK | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	14.8
Fair Value, Inputs, Level 1 | Preferred and Common Stock | U.S.
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		116.0
Fair Value, Inputs, Level 1 | Preferred and Common Stock | Non U.S.
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		52.9
Fair Value, Inputs, Level 1 | Other Investment | Mutual Funds | Global Large Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	69.6
Fair Value, Inputs, Level 1 | Other Investment | Mutual Funds | Foreign Large Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		66.6
Fair Value, Inputs, Level 1 | Other Investment | Mutual Funds | Domestic Large Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		69.4
Fair Value, Inputs, Level 1 | Other Investment | Commodity Linked Fund
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		39.7
Fair Value, Inputs, Level 1 | Other Investment | Ishares Index Fund
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		2.4
Fair Value, Inputs, Level 1 | Cash and Other
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	9.3	5.5
Fair Value, Inputs, Level 2
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	1,229.5	886.8
Fair Value, Inputs, Level 2 | Preferred and Common Stock | Non U.S.
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value		3.9
Fair Value, Inputs, Level 2 | Fixed Income | U.S. Government Sponsored Agency
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	159.5	131.7
Fair Value, Inputs, Level 2 | Other Investment | Collective Trust Fund | Foreign Large Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	105.4	74.3
Fair Value, Inputs, Level 2 | Other Investment | Collective Trust Fund | Foreign Small Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	37.2	31.6
Fair Value, Inputs, Level 2 | Other Investment | Collective Trust Fund | Domestic Large Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	196.7	101.0
Fair Value, Inputs, Level 2 | Other Investment | Collective Trust Fund | Domestic Small Cap Value
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	26.5	26.3
Fair Value, Inputs, Level 2 | Other Investment | Collective Trust Fund | Domestic Mid Cap Value
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	14.4	19.1
Fair Value, Inputs, Level 2 | Other Investment | Collective Trust Fund | Domestic Small Cap Growth
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	21.2	14.3
Fair Value, Inputs, Level 2 | Other Investment | Collective Trust Fund | Domestic Mid Cap Growth
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	15.2	38.0
Fair Value, Inputs, Level 2 | Other Investment | Collective Trust Fund | Short-Term Investment
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	3.4	6.6
Fair Value, Inputs, Level 2 | Other Investment | Collective Trust Fund | Global Real Estate Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	73.8	65.4
Fair Value, Inputs, Level 2 | Other Investment | Collective Trust Fund | Domestic Long-Term Bond
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	508.0	333.7
Fair Value, Inputs, Level 2 | Other Investment | Collective Trust Fund | Emerging Market Large Cap Blend
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	68.2	40.9
Fair Value, Inputs, Level 3
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	117.6	102.8
Fair Value, Inputs, Level 3 | Private Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	49.0	47.7	47.4
Fair Value, Inputs, Level 3 | Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	68.6	55.1	30.2
Fair Value, Inputs, Level 3 | Other Investment | Private Equity Funds
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	49.0	47.7
Fair Value, Inputs, Level 3 | Other Investment | Hedge Funds
Defined Benefit Plan Disclosure [Line Items]
Total Assets at Fair Value	$ 68.6	$ 55.1