Pensions and Other Postretirement Benefits (Tables)

3 Months Ended

Jul. 27, 2011

Pensions and Other Postretirement Benefits [Abstract]

Components of net periodic benefit cost

	First Quarter Ended
	July 27, 2011			July 28, 2010			July 27, 2011			July 28, 2010
	Pension Benefits						Other Retiree Benefits
	(Thousands of Dollars)
Service cost	$	8,611		$	7,737		$	1,508		$	1,561
Interest cost		35,547			34,279			2,887			3,154
Expected return on plan assets		(59,781	)		(55,292	)		—			—
Amortization of prior service cost/(credit)		498			591			(1,530	)		(1,290	)
Amortization of unrecognized loss		21,229			18,968			273			401
Net periodic benefit cost	$	6,104		$	6,283		$	3,138		$	3,826