Benefits - Defined benefit plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 01, 2024	Nov. 26, 2023	Nov. 27, 2022
Pension plans, defined benefit [Member]
Net periodic benefit cost (income):
Service cost	$ 2.6	$ 2.8	$ 3.9
Interest cost	39.7	39.9	22.5
Expected return on plan assets	(38.9)	(37.7)	(31.8)
Amortization of prior service benefit	(0.1)	(0.1)	0.0
Amortization of actuarial loss	8.0	8.9	8.5
Curtailment (gain)	(1.7)	0.0	0.0
Net settlement loss (gain)	1.0	18.9	(0.2)
Net periodic benefit cost	10.6	32.7	2.9
Changes in accumulated other comprehensive loss:
Actuarial (gain) loss	(6.9)	(7.9)	(3.3)
Amortization of prior service benefit (cost)	0.1	0.1	0.0
Amortization of actuarial loss	(8.0)	(8.9)	(8.5)
Net settlement (loss) gain	(1.0)	(18.9)	0.2
Total recognized in accumulated other comprehensive loss	(15.8)	(35.6)	(11.6)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	(5.2)	(2.9)	(8.7)
Other postretirement benefit plans, defined benefit [Member]
Net periodic benefit cost (income):
Service cost	0.0	0.0	0.0
Interest cost	2.0	2.0	0.9
Expected return on plan assets	0.0	0.0	0.0
Amortization of prior service benefit	0.0	0.0	0.0
Amortization of actuarial loss	0.0	0.0	0.3
Curtailment (gain)	0.0	0.0	0.0
Net settlement loss (gain)	0.0	0.0	0.0
Net periodic benefit cost	2.0	2.0	1.2
Changes in accumulated other comprehensive loss:
Actuarial (gain) loss	0.5	1.0	(10.2)
Amortization of prior service benefit (cost)	0.0	0.0	0.0
Amortization of actuarial loss	0.0	0.0	(0.3)
Net settlement (loss) gain	0.0	0.0	0.0
Total recognized in accumulated other comprehensive loss	0.5	1.0	(10.5)
Total recognized in net periodic benefit cost and accumulated other comprehensive loss	$ 2.5	$ 3.0	$ (9.3)