Debt Obligations and Commitments - Additional Information (Detail) (USD $)			3 Months Ended		6 Months Ended
	Jun. 15, 2013	Jun. 15, 2013 Four Year Unsecured Revolving Credit Agreement	Jun. 15, 2013 Three Sixty Four Day Unsecured Revolving Credit Agreement	Jun. 15, 2013 Five Year Unsecured Revolving Credit Agreement	Jun. 15, 2013 Notes Due 2016 Floating Rate Notes Due 2016	Mar. 23, 2013 Notes Due 2016 Floating Rate Notes Due 2016	Mar. 23, 2013 Notes Due 2016 0.700% Senior Notes Due 2016	Mar. 23, 2013 Notes Due 2023 2.75000% Senior Notes Due 2023
Debt Instrument [Line Items]
Fixed and floating rate notes issued						$ 625,000,000	$ 625,000,000	$ 1,250,000,000
LIBOR term					3 months
Basis spread on LIBOR					0.21%
Interest rate on debt							0.70%	2.75%
Line of Credit Facility, Expiration Date			Jun. 09, 2014	Jun. 10, 2018
Debt Instrument, Term of Agreement			364 days	5 years
Line of Credit Facility, Maximum Borrowing Capacity			2,925,000,000	2,925,000,000
Line Of Credit Facility Increase Additional Borrowing Capacity			3,500,000,000	3,500,000,000
Line of Credit Facility Replaced		2,925,000,000	2,925,000,000
Commercial paper outstanding	$ 2,400,000,000