Retirement Plans - Narrative (Details) - Pension Plan - USD ($)	12 Months Ended
	Dec. 31, 2020	Jun. 30, 2021
Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected future employer contributions, current fiscal year	$ 0
Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Pension plan contribution	$ 5,000,000
Defined benefit plan, expected future employer contributions, current fiscal year		$ 5,000,000