Pension and Other Postretirement Benefit Plans 3 (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 29, 2012	Apr. 27, 2011	Apr. 28, 2010
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 33,719	$ 32,329	$ 30,486
Interest cost	139,525	142,133	149,640
Expected return on assets	(234,717)	(229,258)	(211,408)
Prior service cost/(credit)	1,995	2,455	2,173
Net actuarial loss	83,800	77,687	53,882
Loss due to curtailment, settlement and special termination benefits	1,120	2,039	612
Net periodic benefit cost	25,442	27,385	25,385
Defined contribution plans	46,572	49,089	47,356
Total cost	72,014	76,474	72,741
Less periodic benefit cost associated with discontinued operations	0	0	618
Periodic benefit cost associated with continuing operations	72,014	76,474	72,123
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	5,967	6,311	5,999
Interest cost	11,457	12,712	15,093
Expected return on assets	0	0	0
Prior service cost/(credit)	(6,127)	(5,155)	(3,796)
Net actuarial loss	1,095	1,604	540
Loss due to curtailment, settlement and special termination benefits	0	0	0
Net periodic benefit cost	12,392	15,472	17,836
Defined contribution plans	0	0	0
Total cost	12,392	15,472	17,836
Less periodic benefit cost associated with discontinued operations	0	0	0
Periodic benefit cost associated with continuing operations	$ 12,392	$ 15,472	$ 17,836