Habit Burger Acquisition (Details) $ in Millions		3 Months Ended				6 Months Ended		12 Months Ended
	Mar. 18, 2020 USD ($) restaurants	Jun. 30, 2021 USD ($) restaurants	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Jun. 30, 2021 USD ($) restaurants	Jun. 30, 2020 USD ($)	Mar. 17, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Business Acquisition [Line Items]
Number of Stores | restaurants		51,000				51,000
Acquisition of The Habit Restaurants, Inc., net of cash acquired	$ 408					$ 0	$ 408
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	20
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, Indefinite-Lived Intangible Assets	96
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
Goodwill		$ (597)				(597)				$ (597)
Income tax provision		$ 16		$ 51		$ 99	63
Goodwill impairment tax benefit [Member]
Business Acquisition [Line Items]
Income tax provision			$ 1		$ 32
The Habit Burger Grill [Member]
Business Acquisition [Line Items]
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
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				$ 139