Pension, Savings, and Other Employee Benefits - Schedule of Balances Reflected in AOCI On a Pre-Tax Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Prior service cost/(credit)	$ 0	$ 0
Net actuarial (gain)/loss	362,799	387,058
Total	362,799	387,058
Other Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Prior service cost/(credit)	408	0
Net actuarial (gain)/loss	(1,555)	(6,451)
Total	$ (1,147)	$ (6,451)