Pension and Other Postretirement Benefit Plans 1 (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 29, 2012	Apr. 27, 2011	Apr. 28, 2010
Change in Plan Assets:
Fair value of plan assets at the beginning of the year	$ 3,261,881
Employer contribution	23,500
Fair value of plan assets at the end of the year	3,140,834
Pension Plans, Defined Benefit [Member]
Change in Benefit Obligation:
Benefit obligation at the beginning of the year	2,765,316	2,585,984
Service cost	33,719	32,329	30,486
Interest cost	139,525	142,133	149,640
Participants’ contributions	2,281	2,444
Amendments	3,396	377
Actuarial loss/(gain)	196,606	(8,457)
Settlement	(1,854)	(3,275)
Benefits paid	(152,342)	(159,307)
Exchange/other	(56,300)	173,088
Benefit obligation at the end of the year	2,930,347	2,765,316	2,585,984
Change in Plan Assets:
Fair value of plan assets at the beginning of the year	3,261,881	2,869,971
Actual return on plan assets	84,004	318,494
Settlement	(1,854)	(3,275)
Employer contribution	23,469	22,411
Participants’ contributions	2,281	2,444
Benefits paid	(152,342)	(159,307)
Exchange/other	(76,605)	211,143
Fair value of plan assets at the end of the year	3,140,834	3,261,881	2,869,971
Funded status	210,487	496,565
Other Postretirement Benefit Plans, Defined Benefit [Member]
Change in Benefit Obligation:
Benefit obligation at the beginning of the year	234,431	235,297
Service cost	5,967	6,311	5,999
Interest cost	11,457	12,712	15,093
Participants’ contributions	712	822
Amendments	735	(3,710)
Actuarial loss/(gain)	17,278	(3,786)
Settlement	0	0
Benefits paid	(19,574)	(16,986)
Exchange/other	(1,989)	3,771
Benefit obligation at the end of the year	249,017	234,431	235,297
Change in Plan Assets:
Fair value of plan assets at the beginning of the year	0	0
Actual return on plan assets	0	0
Settlement	0	0
Employer contribution	18,862	16,164
Participants’ contributions	712	822
Benefits paid	(19,574)	(16,986)
Exchange/other	0	0
Fair value of plan assets at the end of the year	0	0	0
Funded status	$ (249,017)	$ (234,431)