Goodwill, Customer Relationships and Other Intangible Assets - Additional Information (Details) - USD ($)			3 Months Ended		12 Months Ended
	Jan. 31, 2021	Jan. 01, 2021	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment loss	$ 0
Amortization of intangible assets			$ 425,000,000	$ 431,000,000
Intangible assets, gross (including goodwill)			41,600,000,000
Change in Accounting Estimate [Line Items]
Amortization of intangible assets			425,000,000	431,000,000
Net income			$ (475,000,000)	$ (314,000,000)
Basic earnings per common share (in dollars per share)			$ (0.44)	$ (0.29)
Diluted earnings per common share (in dollars per share)			$ (0.44)	$ (0.29)
Reclassification of intangible assets
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of intangible assets			$ 7,000,000
Change in Accounting Estimate [Line Items]
Amortization of intangible assets			7,000,000
Net income			$ 5,000,000
Reclassification of intangible assets | Forecast
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of intangible assets					$ 30,000,000
Change in Accounting Estimate [Line Items]
Amortization of intangible assets					30,000,000
Net income					$ 23,000,000
Basic earnings per common share (in dollars per share)					$ 0.02
Diluted earnings per common share (in dollars per share)					$ 0.02
Reclassification of intangible assets | Right-of-way
Change in Accounting Estimate [Line Items]
Finite-lived intangible assets		$ 268,000,000
Remaining amortization period		9 years