Pension and Other Postretirement Benefit Plans 3 (Details) (USD $)
In Thousands, unless otherwise specified
 1 Months Ended 11 Months Ended 12 Months Ended
Jun. 07, 2013
Dec. 29, 2013
Apr. 28, 2013
Apr. 29, 2012
Apr. 27, 2011
Pension Plan, Defined Benefit [Member]
          
Defined Benefit Plan Disclosure [Line Items]          
Service cost $ 3,967 $ 20,684 $ 31,580 $ 33,719 $ 32,329
Interest cost 13,557 71,850 132,110 139,525 142,133
Expected return on assets (28,784) (116,294) (250,660) (234,717) (229,258)
Prior service credit/(cost) 245 0 2,495 1,995 2,455
Net actuarial loss 10,460 0 75,897 83,800 77,687
Loss due to curtailment, settlement and special termination benefits 17,230   4,524 1,120 2,039
Net periodic benefit (income)/cost 16,675 32,824 (4,054) 25,442 27,385
Defined contribution plans 4,573 24,039 47,382 46,572 49,089
Total cost 21,248 56,863 43,328 72,014 76,474
Other Postretirement Benefit Plans, Defined Benefit [Member]
          
Defined Benefit Plan Disclosure [Line Items]          
Service cost 743 3,550 6,486 5,967 6,311
Interest cost 938 5,053 9,923 11,457 12,712
Expected return on assets 0 0 0 0 0
Prior service credit/(cost) (677) 0 (6,178) (6,127) (5,155)
Net actuarial loss 222 0 1,803 1,095 1,604
Loss due to curtailment, settlement and special termination benefits 0 (1,017) 0 0 0
Net periodic benefit (income)/cost 1,226 7,586 12,034 12,392 15,472
Defined contribution plans 0 0 0 0 0
Total cost $ 1,226 $ 7,586 $ 12,034 $ 12,392 $ 15,472