Habit Burger Acquisition (Details) $ in Millions			3 Months Ended					9 Months Ended		12 Months Ended
	Sep. 07, 2021 USD ($)	Mar. 18, 2020 USD ($) restaurants	Sep. 30, 2021 USD ($) restaurants	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2021 USD ($) restaurants	Sep. 30, 2020 USD ($)	Mar. 17, 2021 USD ($)	Mar. 31, 2021 USD ($)
Business Acquisition [Line Items]
Number of Stores | restaurants			52,000					52,000
Acquisition of The Habit Restaurants, Inc., net of cash acquired		$ 408						$ 0	$ 408
Goodwill, Purchase Accounting Adjustments								2		$ 15
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets		11
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		111
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets		28
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets		442
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities		(68)
Business Combination, Recognized Identifiable Asset Acquired and Liability Assumed, Lease Obligation		(170)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities		(238)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net		204
Income tax provision			$ (77)		$ 33			22	96
Goodwill			(650)	$ (597)				(650)
Goodwill impairment tax benefit [Member]
Business Acquisition [Line Items]
Income tax provision				$ 1		$ 32
The Habit Burger Grill [Member]
Business Acquisition [Line Items]
Acquisition of The Habit Restaurants, Inc., net of cash acquired		408
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents		20
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Indefinite-Lived Intangible Assets		96
Goodwill		$ (204)									$ 60
The Habit Burger Grill [Member] | Company Owned Stores [Member]
Business Acquisition [Line Items]
Number of Stores | restaurants		245
The Habit Burger Grill [Member] | Franchisee Owned Stores [Member]
Business Acquisition [Line Items]
Number of Stores | restaurants		31
Dragontail Systems Limited
Business Acquisition [Line Items]
Acquisition of The Habit Restaurants, Inc., net of cash acquired	$ 66
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	3
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Indefinite-Lived Intangible Assets	11
Goodwill	$ (57)
Lease Agreements [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets		$ 196
Goodwill [Member]
Business Acquisition [Line Items]
Impairment expense			$ 5		$ 5		$ 139	$ 144	$ 144