Pensions and Other Post-Retirement Benefits 8 (Details) (USD $) In Thousands	12 Months Ended
	Apr. 27, 2011	Apr. 28, 2010
Changes in fair value of Pension plan level 3 assets
Fair value of plan assets at the end of the year	$ 3,261,881	$ 2,869,971
Level 3 [Member]
Changes in fair value of Pension plan level 3 assets
Fair value of plan assets at the beginning of the year	44,215	47,179
Defined Benefit Plan Acquisitions Plan Assets	95,518	3,362
Defined Benefit Plan Dispositions Plan Assets	(619)	(4,158)
Defined Benefit Plan Realized Gain Loss	2,727	(2,381)
Defined Benefit Plan Unrealized Gain Loss	(1,097)	213
Fair value of plan assets at the end of the year	140,744	44,215
Level 3 [Member] | Fixed Income Securities [Member]
Changes in fair value of Pension plan level 3 assets
Fair value of plan assets at the beginning of the year	8,646	8,873
Defined Benefit Plan Dispositions Plan Assets		(1,500)
Defined Benefit Plan Realized Gain Loss		246
Defined Benefit Plan Unrealized Gain Loss	1,003	1,027
Fair value of plan assets at the end of the year	9,649	8,646
Level 3 [Member] | Other Investments [Member]
Changes in fair value of Pension plan level 3 assets
Fair value of plan assets at the beginning of the year	35,569	38,306
Defined Benefit Plan Acquisitions Plan Assets	95,518	3,362
Defined Benefit Plan Dispositions Plan Assets	(619)	(2,658)
Defined Benefit Plan Realized Gain Loss	2,727	(2,627)
Defined Benefit Plan Unrealized Gain Loss	(2,100)	(814)
Fair value of plan assets at the end of the year	131,095	35,569
Fixed Income Securities [Member]
Changes in fair value of Pension plan level 3 assets
Fair value of plan assets at the end of the year	1,029,187	844,521
Other Investments [Member]
Changes in fair value of Pension plan level 3 assets
Fair value of plan assets at the end of the year	$ 131,095	$ 43,060