Employee Benefit Plans (Narrative) (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Discontinued Operations Net Pension Expense					$ 4.3
Defined Benefit Plan, Curtailments	$ 0.1		$ 0.1		3.2
Discontinued Operation, Share-based Compensation Expense					5.5
Defined Benefit Plan, Accumulated Other Comprehensive Income Net Gains (Losses), after Tax	330.5
Defined Benefit Plan, Accumulated Other Comprehensive Income Net Prior Service Cost (Credit), after Tax	$ 21.3
Stock options - term for stock options granted, in years	10 years
Stock repurchased during period (in shares)	13.5		13.8
Cash payments for Restricted Stock Units	$ 24.5		$ 25.2		25.2
Aggregate intrinsic value of stock options outstanding and exercisable	112.6
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value	$ 61.2
Weighted average remaining life of stock options outstanding and exercisable	7 years 2 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	5 years 4 months 24 days
Aggregate intrinsic value for options exercised	$ 70.9		85.4		125.3
Award requisite service period	3 years
Additional estimated future contribution in fiscal 2015	$ 9.5
Fair Value of Plan Assets	2,138.4		2,006.3		$ 2,009.8
Defined Benefit Plan, Accumulated Benefit Obligation	1,852.5		1,825.1
Defined Benefit Plan, Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year	10.5
Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit)	2.2
Defined Benefit Plan, Contributions by Employer	11.9		11.0
Expected future plan benefit payment - 2016	85.9
Expected future plan benefit payment - 2017	89.8
Expected future plan benefit payment - 2018	97.1
Expected future plan benefit payment - 2019	107.7
Expected future plan benefit payment - 2020	119.2
Expected future plan benefit payment - 2021 to 2025	$ 718.3
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent	50.00%
Highly Compensated Employee Contribution Percentage To Retirement And Saving Plan	12.00%
Defined Contribution Plan, Cost Recognized		$ 87.9		$ 81.9		$ 69.7
Stock Options Granted After July 2008 [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vesting term options granted	4 years
Time Based Restricted Stock granted during Fiscal 2013 [Domain] [Domain]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vesting term options granted	2 years
Performance Based Restricted Stock and Units [Domain]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Minimum percentage that will ultimately vest under performance-based restricted stock awards based on performance target	0.00%
Maximum percentage that will ultimately vest under performance-based restricted stock awards based on performance target	150.00%
Employee Stock [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Purchase price of common stock as percentage of market value	95.00%
Non-Vested Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total remaining unrecognized compensation cost	$ 12.6
Weighted-average remaining requisite vesting period	2 years 3 months 19 days
Restricted Stock Units (RSUs) [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total remaining unrecognized compensation cost	$ 27.9
Weighted-average remaining requisite vesting period	1 year 3 months 13 days
Non-Vested Restricted Stock [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total remaining unrecognized compensation cost	$ 60.7
Weighted-average remaining requisite vesting period	1 year 1 month 10 days
Minimum [Member] | Performance Based Restricted Stock and Units [Domain]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Performance Period	1 year
Maximum [Member] | Performance Based Restricted Stock and Units [Domain]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vesting term options granted	26 months
Share Based Compensation Arrangement By Share Based Payment Award Performance Period	3 years
Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Fair Value of Plan Assets	$ 15.2		$ 60.3