Commitments and Contingencies (Details) $ in Millions			1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 27, 2021 claim	Sep. 09, 2019 defendant	Oct. 31, 2018 USD ($)	Mar. 31, 2021 USD ($) claim	Dec. 31, 2020 USD ($) claim	Dec. 31, 2019 USD ($)	Mar. 31, 2020 lawsuit	Jan. 23, 2020 claim	Aug. 01, 2018 lawsuit
Commitments and Contingencies Disclosure [Abstract]
Outstanding letters of credit and surety bonds | $				$ 142
Loss Contingencies [Line Items]
Lawsuits consolidated | lawsuit							3
Number of claims dismissed | claim	1
Number of consolidated class action lawsuits | claim								4
Number of law firms retained | lawsuit									2
Contributions to grantor trust | $			$ 120
Number of defendants | defendant		14
Costs for settlement and defense of asbestos claims, net of insurance recoveries and taxes | $					$ 35	$ 58
Asbestos Claims [Member]
Loss Contingencies [Line Items]
Number of pending asbestos claims | claim				30,480	30,710
Number of new asbestos claims | claim				780
Number of asbestos claims closed or moved to inactive docket | claim				1,010
CBS Television City [Member]
Loss Contingencies [Line Items]
Guaranteed cash flow period						5 years
Estimated liability | $				$ 75
Famous Players [Member]
Loss Contingencies [Line Items]
Estimated liability | $				$ 67