OTHER COMPREHENSIVE INCOME OR LOSS - Changes in the AOCI Balance (Details) - USD ($) $ in Millions	12 Months Ended
	Feb. 27, 2021	Feb. 29, 2020	Feb. 23, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning AOCI balance	$ 2,278.1	$ 1,450.7	$ 1,398.2
Other comprehensive income (loss) before reclassifications	242.5	(356.2)
Amounts reclassified from Accumulated other comprehensive income (loss)	2.8	46.9
Tax (expense) benefit	(63.3)	82.9
Other comprehensive income (loss)	182.0	(209.8)	(99.8)
Ending AOCI balance	1,324.3	2,278.1	1,450.7
Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning AOCI balance		574.6
Ending AOCI balance			574.6
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning AOCI balance	(118.5)	91.3	191.1
Ending AOCI balance	63.5	(118.5)	91.3
Total | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning AOCI balance		16.6
Ending AOCI balance			16.6
Interest rate swaps
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning AOCI balance	0.0	3.4
Other comprehensive income (loss) before reclassifications	0.0	(45.8)
Amounts reclassified from Accumulated other comprehensive income (loss)	0.0	35.4
Tax (expense) benefit	0.0	5.8
Other comprehensive income (loss)	0.0	(3.4)
Ending AOCI balance	0.0	0.0	3.4
Interest rate swaps | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning AOCI balance		1.2
Ending AOCI balance			1.2
Pension and Post-retirement benefit plan items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning AOCI balance	(121.7)	88.8
Other comprehensive income (loss) before reclassifications	244.5	(315.2)
Amounts reclassified from Accumulated other comprehensive income (loss)	2.8	11.5
Tax (expense) benefit	(64.3)	78.3
Other comprehensive income (loss)	183.0	(210.5)
Ending AOCI balance	61.3	(121.7)	88.8
Pension and Post-retirement benefit plan items | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning AOCI balance		14.9
Ending AOCI balance			14.9
Other
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning AOCI balance	3.2	(0.9)
Other comprehensive income (loss) before reclassifications	(2.0)	4.8
Amounts reclassified from Accumulated other comprehensive income (loss)	0.0	0.0
Tax (expense) benefit	1.0	(1.2)
Other comprehensive income (loss)	(1.0)	4.1
Ending AOCI balance	$ 2.2	3.2	(0.9)
Other | Cumulative Effect, Period of Adoption, Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning AOCI balance		$ 0.5
Ending AOCI balance			$ 0.5