Accumulated Other Comprehensive Income (Loss) - Reclassifications Out of Accumulated OCI (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jan. 02, 2021	Sep. 26, 2020	Jun. 27, 2020	Mar. 28, 2020	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense									$ (54.0)	$ (49.0)	$ (50.4)
Income tax expense									(189.1)	(211.8)	(214.4)
Amortization of net unrecognized losses and prior service credits									8.7	8.8	4.2
Net earnings	$ 213.8	$ 184.7	$ 105.9	$ 142.0	$ 175.0	$ 169.2	$ 184.9	$ 182.1	646.4	711.2	$ 696.2
Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net earnings									(24.5)	(16.2)
Cash Flow Hedges | Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest expense									1.6	1.5
Income tax expense									0.0	0.0
Net earnings									1.6	1.5
Defined Benefit Pension and Postretirement Plans | Reclassification out of AOCI
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense									8.4	5.8
Amortization of net unrecognized losses and prior service credits									(34.5)	(23.5)
Net earnings									$ (26.1)	$ (17.7)