Receivables - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012
Sold receivables that remain uncollected	$ 89
Sale of customer receivables			304
Cash received for receivables			50
Deferred purchase price receivable			254
Additional funding received	50	100
Purchase price receivable	81
Accounts receivables	2,172
Cash collections	1,891
Maximum [Member]
Funding of customer receivables sold			250
Minimum [Member]
Funding of customer receivables sold			$ 50