Benefits - Amounts recognized in balance sheet (Details) - USD ($) $ in Millions	Nov. 26, 2023	Nov. 27, 2022
Pension plans, defined benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Assets for Plan Benefits, Defined Benefit Plan	$ 87.6	$ 75.2
Accrued benefit liability – current portion(2)	(10.3)	(9.7)
Accrued benefit liability – long-term portion(2)	(107.3)	(109.6)
Amount recognized in balance sheet	(30.0)	(44.1)
Accumulated other comprehensive loss:
Net actuarial loss	(217.5)	(253.1)
Net prior service benefit	0.1	0.1
Other comprehensive income (loss)	(217.4)	(253.0)
Other postretirement benefit plans, defined benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Assets for Plan Benefits, Defined Benefit Plan	0.0	0.0
Accrued benefit liability – current portion(2)	(5.6)	(5.7)
Accrued benefit liability – long-term portion(2)	(33.6)	(36.2)
Amount recognized in balance sheet	(39.2)	(41.9)
Accumulated other comprehensive loss:
Net actuarial loss	0.6	1.6
Net prior service benefit	0.0	0.0
Other comprehensive income (loss)	$ 0.6	$ 1.6