Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impairment losses	$ 258	$ 0	$ 0
Other intangible assets, operating lease right-of-use assets and property and equipment [member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Impairment losses	$ 139
Growth rate | Goodwill [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value measurement technique	2.5 percent
Growth rate | Other intangible assets, operating lease right-of-use assets and property and equipment [member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value measurement technique	1.7 percent to 4.8 percent
Discount rate | Goodwill [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value measurement technique	12.0 percent
Discount rate | Other intangible assets, operating lease right-of-use assets and property and equipment [member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value measurement technique	7.0 percent to 12.0 percent