Pension and Other Postretirement Benefit Plans 6 (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended									12 Months Ended																																										12 Months Ended
	Apr. 28, 2013	Apr. 29, 2012	Apr. 28, 2013 Fair Value, Inputs, Level 1 [Member]	Apr. 29, 2012 Fair Value, Inputs, Level 1 [Member]	Apr. 28, 2013 Fair Value, Inputs, Level 2 [Member]	Apr. 29, 2012 Fair Value, Inputs, Level 2 [Member]	Apr. 28, 2013 Fair Value, Inputs, Level 3 [Member]	Apr. 29, 2012 Fair Value, Inputs, Level 3 [Member]	Apr. 27, 2011 Fair Value, Inputs, Level 3 [Member]	Apr. 28, 2013 Equity Securities [Member]	Apr. 29, 2012 Equity Securities [Member]	Apr. 28, 2013 Equity Securities [Member] Fair Value, Inputs, Level 1 [Member]	Apr. 29, 2012 Equity Securities [Member] Fair Value, Inputs, Level 1 [Member]	Apr. 28, 2013 Equity Securities [Member] Fair Value, Inputs, Level 2 [Member]	Apr. 29, 2012 Equity Securities [Member] Fair Value, Inputs, Level 2 [Member]	Apr. 28, 2013 Equity Securities [Member] Fair Value, Inputs, Level 3 [Member]	Apr. 29, 2012 Equity Securities [Member] Fair Value, Inputs, Level 3 [Member]	Apr. 28, 2013 Equity Funds [Member]	Apr. 29, 2012 Equity Funds [Member]	Apr. 28, 2013 Equity Funds [Member] Fair Value, Inputs, Level 1 [Member]	Apr. 29, 2012 Equity Funds [Member] Fair Value, Inputs, Level 1 [Member]	Apr. 28, 2013 Equity Funds [Member] Fair Value, Inputs, Level 2 [Member]	Apr. 29, 2012 Equity Funds [Member] Fair Value, Inputs, Level 2 [Member]	Apr. 28, 2013 Equity Funds [Member] Fair Value, Inputs, Level 3 [Member]	Apr. 29, 2012 Equity Funds [Member] Fair Value, Inputs, Level 3 [Member]	Apr. 28, 2013 Fixed Income Funds [Member]	Apr. 29, 2012 Fixed Income Funds [Member]	Apr. 28, 2013 Fixed Income Funds [Member] Fair Value, Inputs, Level 1 [Member]	Apr. 29, 2012 Fixed Income Funds [Member] Fair Value, Inputs, Level 1 [Member]	Apr. 28, 2013 Fixed Income Funds [Member] Fair Value, Inputs, Level 2 [Member]	Apr. 29, 2012 Fixed Income Funds [Member] Fair Value, Inputs, Level 2 [Member]	Apr. 28, 2013 Fixed Income Funds [Member] Fair Value, Inputs, Level 3 [Member]	Apr. 29, 2012 Fixed Income Funds [Member] Fair Value, Inputs, Level 3 [Member]	Apr. 27, 2011 Fixed Income Funds [Member] Fair Value, Inputs, Level 3 [Member]	Apr. 28, 2013 Other Investments [Member]	Apr. 29, 2012 Other Investments [Member]	Apr. 28, 2013 Other Investments [Member] Fair Value, Inputs, Level 1 [Member]	Apr. 29, 2012 Other Investments [Member] Fair Value, Inputs, Level 1 [Member]	Apr. 28, 2013 Other Investments [Member] Fair Value, Inputs, Level 2 [Member]	Apr. 29, 2012 Other Investments [Member] Fair Value, Inputs, Level 2 [Member]	Apr. 28, 2013 Other Investments [Member] Fair Value, Inputs, Level 3 [Member]	Apr. 29, 2012 Other Investments [Member] Fair Value, Inputs, Level 3 [Member]	Apr. 27, 2011 Other Investments [Member] Fair Value, Inputs, Level 3 [Member]	Apr. 28, 2013 Cash and Cash Equivalents [Member]	Apr. 29, 2012 Cash and Cash Equivalents [Member]	Apr. 28, 2013 Cash and Cash Equivalents [Member] Fair Value, Inputs, Level 1 [Member]	Apr. 29, 2012 Cash and Cash Equivalents [Member] Fair Value, Inputs, Level 1 [Member]	Apr. 28, 2013 Cash and Cash Equivalents [Member] Fair Value, Inputs, Level 2 [Member]	Apr. 29, 2012 Cash and Cash Equivalents [Member] Fair Value, Inputs, Level 2 [Member]	Apr. 28, 2013 Cash and Cash Equivalents [Member] Fair Value, Inputs, Level 3 [Member]	Apr. 29, 2012 Cash and Cash Equivalents [Member] Fair Value, Inputs, Level 3 [Member]	Apr. 28, 2013 Debt Securities [Member]	Apr. 29, 2012 Debt Securities [Member]	Apr. 28, 2013 Real Estate [Member]	Apr. 29, 2012 Real Estate [Member]	Apr. 28, 2013 Other Assets [Member]	Apr. 29, 2012 Other Assets [Member]	Apr. 28, 2013 Maximum [Member] Common Stock [Member]	Apr. 29, 2012 Maximum [Member] Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity securities	100.00%	100.00%								62.00%	61.00%																																									29.00%	31.00%	8.00%	7.00%	1.00%	1.00%	1.00%	1.00%
Equity securities, target allocation	100.00%	100.00%								58.00%	59.00%																																									33.00%	32.00%	8.00%	8.00%	1.00%	1.00%
Fair value of plan assets	$ 3,379,143	$ 3,140,834	$ 1,121,168	$ 1,056,416	$ 1,989,858	$ 1,857,698	$ 268,117	$ 226,720	$ 140,744	$ 882,081	$ 822,184	$ 882,081	$ 822,184	$ 0	$ 0	$ 0	$ 0	$ 1,239,834	$ 1,091,610	$ 182,723	$ 147,865	$ 1,057,111	$ 943,745	$ 0	$ 0	$ 980,296	$ 981,496	$ 49,577	$ 76,032	$ 919,383	$ 894,978	$ 11,336	$ 10,486	$ 9,649	$ 256,781	$ 216,234	$ 0	$ 0	$ 0	$ 0	$ 256,781	$ 216,234	$ 131,095	$ 20,151	$ 29,310	$ 6,787	$ 10,335	$ 13,364	$ 18,975	$ 0	$ 0