Other Post-Employment Benefits and Other Employee Benefit Plans - Estimated Future Benefit Payments (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
2015	$ 45.4
2016	45.9
2017	47.7
2018	49.0
2019	50.5
Thereafter	279.4
Total	517.9
Other Post-Employment Benefits and Other Employee Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
2015	5.4
2016	5.3
2017	5.3
2018	5.3
2019	5.4
Thereafter	26.0
Total	$ 52.7