Pension and Other Postretirement Benefit Plans 9 (Details) (USD $)	12 Months Ended
	Apr. 28, 2013	Apr. 29, 2012
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Accumulated Benefit Obligation	$ 3,110,000,000	$ 2,790,000,000
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Accumulated Benefit Obligation	631,700,000	630,300,000
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit Obligation	640,800,000	642,300,000
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets	460,900,000	452,900,000
Defined Benefit Plan, Contributions by Employer	69,400,000
Defined benefit plan, employer discretioinary contribution amount	33,100,000
Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets, Aggregate Benefit Obligation	900,300,000	642,300,000
Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets	720,500,000	452,900,000
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax	(255,700,000)	(353,100,000)
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax	(82,900,000)	(87,300,000)
Defined Benefit Plan, Contributions by Employer	69,388,000	23,469,000
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	100,000,000
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax	(9,100,000)	(18,000,000)
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax	4,400,000	5,000,000
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year	6.30%
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	4.80%
Defined Benefit Plan, Contributions by Employer	15,101,000	18,862,000
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	17,100,000
Defined Benefit Plan, Gross Prescription Drug Subsidy Receipts Received	$ 500,000