Changes to Debt (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Debt Instrument [Line Items]
Debt maturing within one year, Balance at January 1, 2013	$ 4,369
Long-term debt, Balance at January 1, 2013	47,618
Total, Balance at January 1, 2013	51,987
Proceeds from long-term borrowings	499
Repayments of long-term borrowings and capital leases obligations	(2,330)	(1,891)
Decrease in short-term obligations, excluding current maturities	(432)	(887)
Other	28
Debt maturing within one year, Balance at June 30, 2013	7,961
Long-term debt, Balance at June 30, 2013	41,791
Total, Balance at June 30, 2013	49,752
Long-term Debt
Debt Instrument [Line Items]
Long-term debt, Balance at January 1, 2013	47,618
Proceeds from long-term borrowings	499
Repayments of long-term borrowings and capital leases obligations	(250)
Reclassifications of long-term debt	(6,021)
Other	(55)
Long-term debt, Balance at June 30, 2013	41,791
Debt Maturing Within One Year
Debt Instrument [Line Items]
Debt maturing within one year, Balance at January 1, 2013	4,369
Repayments of long-term borrowings and capital leases obligations	(2,080)
Decrease in short-term obligations, excluding current maturities	(432)
Reclassifications of long-term debt	6,021
Other	83
Debt maturing within one year, Balance at June 30, 2013	$ 7,961