Employee Benefits (Weighted Average Assumptions - Net Periodic Benefit Cost) (Details) - Other Postretirement Benefit Plan - USD ($) $ in Millions				12 Months Ended
		Jan. 01, 2020	Jan. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, One Percentage Point Change, Increase or Decrease				1.00%
Defined Benefit Plan, Effect of One Percentage Point Increase on Benefit Obligations				$ 10.6
Defined Benefit Plan, Effect of One Percentage Point Decrease on Benefit Obligations				8.3
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components				1.0
Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components				$ 0.8
Net Periodic Benefit Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected long-term return on plan assets				6.00%	6.12%	4.875%
Ultimate				4.50%	4.50%	4.50%
Year ultimate reached	[1]			2026	2026	2026
Benefit Obligation | Net Periodic Benefit Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount Rate				4.44%	3.79%	4.37%
Service cost | Net Periodic Benefit Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount Rate				4.51%	3.87%	4.59%
Interest cost | Net Periodic Benefit Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount Rate				4.15%	3.38%	3.76%
Pre-65 medical | Net Periodic Benefit Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Initial				6.00%	6.25%	6.50%
Post-65 medical | Net Periodic Benefit Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Initial				4.50%	4.50%	4.50%
Pre-65 drug | Net Periodic Benefit Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Initial				7.00%	7.25%	7.50%
Post-65 drug | Net Periodic Benefit Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Initial				8.50%	10.00%	10.50%
Pre-tax gross basis | Subsequent Event | Net Periodic Benefit Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected long-term return on plan assets		7.85%
After-tax gross basis | Subsequent Event | Net Periodic Benefit Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected long-term return on plan assets		6.00%
Trust tax rate | Net Periodic Benefit Costs
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Trust tax rate		23.60%	23.60%

[1] Pre-65 medical reaches the ultimate trend rate in 2025. Additionally, the Post-65 medical trend is assumed to be 4.50% for all years into the future