Pensions and Other Postretirement Plans (Key Assumptions - Cost) (Details 6) - Periodic Cost [Member]	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 23, 2018	[1]	Dec. 31, 2018	[1]	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (percent)	3.60%		4.00%		4.30%		4.10%
Expected return on plan assets (percent)					6.25%	6.25%	6.25%
Cash balance interest crediting rate					3.45%	2.23%	1.57%
Ultimate cash balance interest crediting rate					4.30%	3.00%	3.00%
Year that reaches ultimate cash balance interest crediting rate					2021	2020	2020
Pension Plans [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase (percent)					1.00%	1.00%	1.00%
Pension Plans [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase (percent)					5.00%	5.00%	5.00%
Supplemental Executive Retirement Plan (SERP) [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate (percent)					4.30%	3.60%	4.10%
Expected return on plan assets (percent)					0.00%	0.00%	0.00%
Cash balance interest crediting rate					0.00%	0.00%	0.00%
Supplemental Executive Retirement Plan (SERP) [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase (percent)					1.00%	1.00%	1.00%
Supplemental Executive Retirement Plan (SERP) [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase (percent)					5.00%	5.00%	5.00%

[1] As a result of the Kaplan University transaction, the Company remeasured the accumulated and projected benefit obligation of the pension plan as of March 22, 2018. The remeasurement changed the discount rate from 3.6% for the period January 1 to March 23, 2018 to 4.0% for the period after March 23, 2018.