Employee Benefit Plans (Narrative) (Details) shares in Millions, $ in Millions				12 Months Ended
	Jul. 01, 2019	May 01, 2018 associate	Mar. 01, 2018 associate	Jun. 30, 2019 USD ($) shares	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($) shares	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock options - term for stock options granted, in years				10 years
Vesting term options granted				4 years
Stock repurchased during period (in shares) | shares				6.5		8.5
Cash payments for Restricted Stock Units				$ 26.6		$ 27.1		$ 24.5
Aggregate intrinsic value of stock options outstanding and exercisable				225.2
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Aggregate Intrinsic Value				$ 101.7
Weighted average remaining life of stock options outstanding and exercisable				7 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term				6 years
Aggregate intrinsic value for options exercised				$ 78.2		60.0		70.9
Award requisite service period				3 years
VERP Minimum Age Requirement			55 years
VERP Minimum Period			10 years
VERP Number of Eligible Associates | associate			3,500
VERP Percent of Eligible Associates from Total			6.00%
Associates Opting to Participate in VERP | associate		2,200
VERP Period of Health Care Coverage Following Retirement				24 months
VERP Expenses in SG&A				$ 23.6
Defined Benefit Plan, Accumulated Benefit Obligation				1,938.0		2,121.1
Defined Benefit Plan, Accumulated Other Comprehensive Income Net Gains (Losses), after Tax				281.9
Defined Benefit Plan, Accumulated Other Comprehensive Income Net Prior Service Cost (Credit), after Tax				16.1
Defined Benefit Plan, Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year				8.0
Defined Benefit Plan, Expected Amortization of Prior Service Cost (Credit), Next Fiscal Year				2.2
Defined Benefit Plan, Plan Assets, Contributions by Employer				10.0		10.9
Expected future plan benefit payment - 2019				134.9
Expected future plan benefit payment - 2020				87.8
Expected future plan benefit payment - 2021				95.9
Expected future plan benefit payment - 2022				103.7
Expected future plan benefit payment - 2023				112.4
Expected future plan benefit payment - 2024 to 2028				707.3
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment				48.7		319.5		0.1
Fair Value of Plan Assets				1,910.5		2,178.1		$ 2,138.4
Additional estimated future contribution				$ 9.3
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					$ 110.9		$ 100.6		$ 87.9
Time Based Restriced Stock granted during or after Fiscal 2019 [Domain]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Vesting term options granted				3 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				$ 15.3
Weighted-average remaining requisite vesting period				2 years 5 months
Restricted Stock Units (RSUs) [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total remaining unrecognized compensation cost				$ 51.4
Weighted-average remaining requisite vesting period				1 year 7 months
Non-Vested Restricted Stock [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total remaining unrecognized compensation cost				$ 75.9
Weighted-average remaining requisite vesting period				1 year 11 months
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				38 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				$ 15.0		13.2
Subsequent Event [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Supplemental Officers Retirement Plan Freeze Date	Jul. 01, 2019
Non-Cash Settlement [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
VERP Expenses				$ 48.2
Special Termination Benefits [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
VERP Expenses						$ 319.6