Employee Benefit Plan Obligations Estimated amounts to be amortized from AOCI into net periodic benefit cost over the next fiscal year (Details) - USD ($) $ in Millions	12 Months Ended
	Feb. 24, 2017	Feb. 26, 2016
Pension Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Amortization of Net Gains (Losses)	$ (7.6)	$ (0.8)
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit)	(0.2)	(0.2)
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	7.4	0.6
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Amortization of Net Gains (Losses)	3.7	0.8
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit)	(7.0)	(8.6)
Pension and Other Postretirement Benefit Plans, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year	$ (10.7)	$ (9.4)