Debt (Details) - Senior Notes $ in Millions	Feb. 29, 2024 USD ($)
CNA Financial | 5.1% Senior Notes Due February 15, 2034
Debt [Abstract]
Face amount	$ 500
Interest rate (as a percent)	5.10%
CNA Financial | 4.0% Senior Notes Due May, 2024
Debt [Abstract]
Interest rate (as a percent)	4.00%
Long term debt	$ 550
Transportation and storage of natural gas and NGLs and ethane supply and transportation services – Boardwalk Pipelines | 5.6% Senior Notes Due August 1, 2034
Debt [Abstract]
Face amount	$ 600
Interest rate (as a percent)	5.60%
Transportation and storage of natural gas and NGLs and ethane supply and transportation services – Boardwalk Pipelines | 5.0% Notes Due December 2024
Debt [Abstract]
Interest rate (as a percent)	5.00%
Long term debt	$ 600