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LONG-TERM DEBT AND FINANCE LEASE OBLIGATIONS - Senior Unsecured, Secured Note, Safeway Notes and NALP Notes (Details) - USD ($)								12 Months Ended
	Jan. 04, 2021	Sep. 16, 2020	Sep. 11, 2020	Aug. 31, 2020	Aug. 15, 2020	May 24, 2019	Feb. 06, 2019	Feb. 27, 2021	Feb. 29, 2020	Feb. 23, 2019	Dec. 22, 2020	Feb. 05, 2020	Nov. 22, 2019	Aug. 15, 2019	Feb. 05, 2019
Debt Instrument [Line Items]
Gain (loss) on debt extinguishment								$ (85,300,000)	$ (111,400,000)	$ (8,700,000)
Make-whole premium in debt extinguishment								71,600,000	0
ABL Facility, senior secured and unsecured notes, term loans and debentures								463,400,000	565,300,000	698,300,000
Repayments of long-term debt								4,446,700,000	5,676,600,000	$ 3,082,300,000
Notes payable \| Safeway Notes Repurchase
Debt Instrument [Line Items]
Gain (loss) on debt extinguishment									(11,300,000)
Par value of note repurchased									333,700,000
Book value of debt									322,400,000
Repurchase amount of debt									333,700,000
ABL Facility, senior secured and unsecured notes, term loans and debentures									7,700,000
Notes payable \| Safeway Inc. Notes due 2021 to 2031, interest rate range of 4.75% to 7.45%
Debt Instrument [Line Items]
Gain (loss) on debt extinguishment						$ (500,000)
Par value of note repurchased						34,100,000
Book value of debt						33,300,000
ABL Facility, senior secured and unsecured notes, term loans and debentures						700,000
Repayments of long-term debt						32,600,000
Notes payable \| NALP Notes Repurchase 2018
Debt Instrument [Line Items]
Gain (loss) on debt extinguishment									5,700,000
Par value of note repurchased									108,400,000
Book value of debt									96,400,000
Repurchase amount of debt									90,700,000
ABL Facility, senior secured and unsecured notes, term loans and debentures									$ 1,200,000
Notes payable \| NALP Notes Tender
Debt Instrument [Line Items]
Gain (loss) on debt extinguishment						(19,100,000)
Par value of note repurchased						402,900,000
Book value of debt						363,700,000
Repurchase amount of debt						382,700,000
ABL Facility, senior secured and unsecured notes, term loans and debentures						$ 8,200,000
Notes payable \| NALP Notes Repurchase 2019
Debt Instrument [Line Items]
Gain (loss) on debt extinguishment								(46,200,000)
Par value of note repurchased								553,900,000
Book value of debt								502,000,000.0
Repurchase amount of debt								547,500,000
ABL Facility, senior secured and unsecured notes, term loans and debentures								$ 11,300,000
Senior notes \| Senior Unsecured Notes, Maturity 2026
Debt Instrument [Line Items]
Gain (loss) on debt extinguishment							$ (3,100,000)
Make-whole premium in debt extinguishment							3,100,000
Repurchase amount of debt							268,600,000
ABL Facility, senior secured and unsecured notes, term loans and debentures							$ 6,400,000
Senior notes
Debt Instrument [Line Items]
Cash												$ 18,000,000
Amount of debt extinguished	$ 230,000,000		$ 60,000,000
Gain (loss) on debt extinguishment		$ (8,600,000)		$ (49,100,000)
Make-whole premium in debt extinguishment		7,200,000		41,400,000
Write off of deferred financing costs on previous loans		1,400,000		7,700,000
Senior notes \| Senior Unsecured Notes, Maturity 2026
Debt Instrument [Line Items]
Face amount of debt instrument				$ 750,000,000.0										$ 750,000,000.0	$ 600,000,000.0
Stated interest rate				3.25%										5.875%	7.50%
Senior notes \| Safeway Inc. 5.00% Senior Notes due 2019
Debt Instrument [Line Items]
Stated interest rate							5.00%	5.00%
Senior notes \| Senior Unsecured Notes, Maturity 2027
Debt Instrument [Line Items]
Face amount of debt instrument												600,000,000.0	$ 750,000,000.0
Stated interest rate													4.625%
Senior notes \| Senior Unsecured Notes, Maturity 2023
Debt Instrument [Line Items]
Face amount of debt instrument												$ 750,000,000.0
Stated interest rate												3.50%
Senior notes \| Senior Unsecured Notes, Maturity 2030
Debt Instrument [Line Items]
Face amount of debt instrument												$ 1,000,000,000.0
Stated interest rate												4.875%
Senior notes \| Senior Unsecured Notes, Maturity 2024
Debt Instrument [Line Items]
Face amount of debt instrument			$ 1,250,000,000.0
Stated interest rate			6.625%
Senior notes \| Senior Unsecured Notes, Maturity 2025
Debt Instrument [Line Items]
Face amount of debt instrument	1,000,000,000.0	$ 1,250,000,000.0
Stated interest rate		5.75%
Amount of debt extinguished	800,000,000.0	$ 250,000,000.0
Gain (loss) on debt extinguishment	(27,600,000)
Make-whole premium in debt extinguishment	23,000,000.0
Write off of deferred financing costs on previous loans	$ 4,600,000
Senior notes \| Senior Unsecured Notes Maturity 2029
Debt Instrument [Line Items]
Face amount of debt instrument				$ 750,000,000.0							$ 600,000,000.0
Stated interest rate				3.50%
Senior notes \| Safeway Inc. 7.45% Senior Debentures due 2027
Debt Instrument [Line Items]
Stated interest rate									7.45%
Notes payable \| Safeway Inc. 7.25% Debentures due 2031
Debt Instrument [Line Items]
Stated interest rate									7.25%
Notes payable \| Safeway Notes Maturity 2020
Debt Instrument [Line Items]
Stated interest rate					3.95%
Amount of debt extinguished					$ 136,800,000