Employee Retirement Plans and Postretirement Benefits Projected Benefit Obligation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change in benefit obligation:
Prior year benefit obligation	$ 5,576.8	$ 6,388.0
Service cost, net of expected employee contributions	10.3	14.0
Interest cost	187.4	187.6
Actual employee contributions	0.5	0.6
Actuarial loss (gain)	540.8	(451.1)
Amendments and special termination benefits	(1.4)	7.5
Benefits paid	(394.7)	(340.9)
Curtailment and settlement	(193.1)	(0.6)
Foreign currency exchange rate change	144.5	(228.3)
Benefit obligation at end of year	5,871.1	5,576.8
Change in plan assets:
Prior year fair value of assets	5,217.3	5,897.7
Actual return on plan assets	712.2	(156.1)
Employer contributions	49.2	53.0
Actual employee contributions	0.5	0.6
Settlement	(192.9)	(0.6)
Benefits and plan expenses paid	(394.7)	(340.9)
Foreign currency exchange rate change	150.5	(236.4)
Fair value of plan assets at end of year	5,542.1	5,217.3
Funded status:			$ (329.0)	$ (359.5)
Amounts recognized in the Consolidated Balance Sheets:
Other non-current assets			434.3	416.7
Accounts payable and other current liabilities			(46.7)	(49.6)
Pension and postretirement benefits			(716.6)	(726.6)
Net amounts recognized			(329.0)	(359.5)
Funded status:
Projected benefit obligation	5,871.1	6,388.0	5,871.1	5,576.8	$ 6,388.0
Fair value of plan assets	5,542.1	5,897.7	5,542.1	5,217.3	5,897.7
Amounts in Accumulated Other Comprehensive Loss (Income) not yet recognized as components of net periodic pension cost or (benefit), pre-tax:
Net actuarial (gain) loss			518.2	496.1
Net prior service cost			2.2	4.6
Total not yet recognized			520.4	500.7	562.0
Pension Plan [Member]
Change in benefit obligation:
Prior year benefit obligation	4,904.7	5,584.4
Service cost, net of expected employee contributions	3.3	4.7
Interest cost	161.9	161.8
Actual employee contributions	0.5	0.6
Actuarial loss (gain)	533.4	(342.3)
Amendments and special termination benefits	(1.4)	10.7
Benefits paid	(350.6)	(296.8)
Curtailment and settlement	(192.9)	(0.6)
Foreign currency exchange rate change	139.7	(217.8)
Benefit obligation at end of year	5,198.6	4,904.7
Change in plan assets:
Prior year fair value of assets	5,217.3	5,897.7
Actual return on plan assets	712.2	(156.1)
Employer contributions	5.1	8.9
Actual employee contributions	0.5	0.6
Settlement	(192.9)	(0.6)
Benefits and plan expenses paid	(350.6)	(296.8)
Foreign currency exchange rate change	150.5	(236.4)
Fair value of plan assets at end of year	5,542.1	5,217.3
Funded status:			343.5	312.6
Amounts recognized in the Consolidated Balance Sheets:
Other non-current assets			434.3	416.7
Accounts payable and other current liabilities			(4.1)	(4.5)
Pension and postretirement benefits			(86.7)	(99.6)
Net amounts recognized			343.5	312.6
Accumulated benefit obligation			5,200.0	4,900.0
Improvement in net underfunded status of aggregate pension and OPEB plans	(30.5)
Funded status:
Accumulated benefit obligation			5,200.0	4,900.0
Projected benefit obligation	5,198.6	5,584.4	5,198.6	4,904.7	5,584.4
Fair value of plan assets	5,217.3	5,217.3	5,542.1	5,217.3	5,897.7
Amounts in Accumulated Other Comprehensive Loss (Income) not yet recognized as components of net periodic pension cost or (benefit), pre-tax:
Net actuarial (gain) loss			685.7	687.8
Net prior service cost			7.1	10.2
Total not yet recognized			692.8	698.0	646.9
Pension Plan [Member] | Accumulated Benefit Obligations In Excess Of Plan Assets [Member]
Amounts recognized in the Consolidated Balance Sheets:
Accumulated benefit obligation			793.6	742.1
Funded status:
Accumulated benefit obligation			793.6	742.1
Pension Plan [Member] | Projected Benefit Obligation In Excess Of Plan Assets [Member]
Change in benefit obligation:
Prior year benefit obligation	742.4
Benefit obligation at end of year	794.0	742.4
Funded status:
Projected benefit obligation	742.4	742.4	794.0	742.4
Pension Plan [Member] | Accumulated Benefit and Projected Benefit Obligations in Excess of Plan Assets [Member]
Change in plan assets:
Prior year fair value of assets	638.3
Fair value of plan assets at end of year	703.2	638.3
Funded status:
Fair value of plan assets	638.3	638.3	703.2	638.3
Other Postretirement Benefits Plan [Member]
Change in benefit obligation:
Prior year benefit obligation	672.1	803.6
Service cost, net of expected employee contributions	7.0	9.3
Interest cost	25.5	25.8
Actual employee contributions	0.0	0.0
Actuarial loss (gain)	7.4	(108.8)
Amendments and special termination benefits	0.0	(3.2)
Benefits paid	(44.1)	(44.1)
Curtailment and settlement	(0.2)	0.0
Foreign currency exchange rate change	4.8	(10.5)
Benefit obligation at end of year	672.5	672.1
Change in plan assets:
Prior year fair value of assets	0.0	0.0
Actual return on plan assets	0.0	0.0
Employer contributions	44.1	44.1
Actual employee contributions	0.0	0.0
Settlement	0.0	0.0
Benefits and plan expenses paid	(44.1)	(44.1)
Foreign currency exchange rate change	0.0	0.0
Fair value of plan assets at end of year	0.0	0.0
Funded status:			(672.5)	(672.1)
Amounts recognized in the Consolidated Balance Sheets:
Other non-current assets			0.0	0.0
Accounts payable and other current liabilities			(42.6)	(45.1)
Pension and postretirement benefits			(629.9)	(627.0)
Net amounts recognized			(672.5)	(672.1)
Funded status:
Projected benefit obligation	672.1	672.1	672.5	672.1	803.6
Fair value of plan assets	$ 0.0	$ 0.0	0.0	0.0	0.0
Amounts in Accumulated Other Comprehensive Loss (Income) not yet recognized as components of net periodic pension cost or (benefit), pre-tax:
Net actuarial (gain) loss			(167.5)	(191.7)
Net prior service cost			(4.9)	(5.6)
Total not yet recognized			$ (172.4)	$ (197.3)	$ (84.9)