Retirement Plans - Reconciliation of Benefit Obligation, Plan Assets and Funded Status of Plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Plan amendments and other	$ (354.8)
Pension Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	3,932.3	$ 4,258.8
Service cost	1.0	1.7	$ 1.9
Interest cost	105.7	170.4	187.8
Plan participants' contributions	0.0	0.0
Medicare reimbursements	0.0	0.0
Actuarial (gain) loss	349.5	(270.2)
Plan amendments and other	0.0	6.2
Curtailments and settlements	(304.4)	0.0
Foreign currency translation	(40.5)	(48.1)
Benefits paid	(129.7)	(186.1)
Divestitures	(23.6)	(0.4)
Acquisitions	0.0	0.0
Benefit obligation at end of year	974.7	3,932.3	4,258.8
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	3,424.1	3,656.5
Actual return on assets	424.1	(24.5)
Settlements	(304.4)	0.0
Employer contributions	12.8	14.9
Medicare reimbursements	0.0	0.0
Plan participants' contributions	0.0	0.0
Divestitures	(16.8)	0.0
Foreign currency translation	(45.6)	(36.7)
Benefits paid	(129.7)	(186.1)
Fair value of plan assets at end of year	875.4	3,424.1	3,656.5
Total net pension liability recognized as of December 31	(99.3)	(508.2)
Pension Benefits | Discontinued Operations
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Divestitures	(2,915.6)	0.0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Divestitures	(2,489.1)	0.0
Total net pension liability recognized as of December 31	0.0	388.4
Pension Benefits | Continuing operations
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Total net pension liability recognized as of December 31	(99.3)	(119.8)
Other Postretirement Benefits
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	373.8	423.1
Service cost	3.8	4.7	4.6
Interest cost	11.7	15.9	16.5
Plan participants' contributions	9.4	10.7
Medicare reimbursements	5.4	5.7
Actuarial (gain) loss	5.9	(46.3)
Plan amendments and other	(33.8)	(0.1)
Curtailments and settlements	0.0	0.0
Foreign currency translation	1.3	(7.8)
Benefits paid	(32.5)	(32.5)
Divestitures	0.0	0.0
Acquisitions	0.0	0.4
Benefit obligation at end of year	345.0	373.8	423.1
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets at beginning of year	205.5	212.6
Actual return on assets	14.8	(1.1)
Settlements	0.0	0.0
Employer contributions	7.7	10.1
Medicare reimbursements	5.4	5.7
Plan participants' contributions	9.4	10.7
Divestitures	0.0	0.0
Foreign currency translation	0.0	0.0
Benefits paid	(32.5)	(32.5)
Fair value of plan assets at end of year	210.3	205.5	$ 212.6
Total net pension liability recognized as of December 31	(134.7)	(168.3)
Other Postretirement Benefits | Discontinued Operations
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Divestitures	0.0	0.0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Divestitures	0.0	0.0
Total net pension liability recognized as of December 31	0.0	0.0
Other Postretirement Benefits | Continuing operations
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Total net pension liability recognized as of December 31	$ (134.7)	$ (168.3)