Pension and Postretirement Plans - Schedule of Weighted-Average Discount Rate Assumptions (Details)	Sep. 08, 2021	Dec. 31, 2020
Pension Plans, Defined Benefit [Member] | Cincinnati Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	2.60%	2.40%
Pension Plans, Defined Benefit [Member] | Hawaii Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	2.50%	2.30%
Other Postretirement Benefits Plan [Member] | Cincinnati Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	2.60%	2.40%
Other Postretirement Benefits Plan [Member] | Hawaii Plans [Member]
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	2.80%	2.60%