Future Minimum Payments Under Non-Cancelable Operating Leases, Along with Sublease Income Amounts (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Schedule of Operating Leases [Line Items]
Operating Leases	$ 3,704
Sub-lease Income	85
Net Operating Leases	3,619
2013
Schedule of Operating Leases [Line Items]
Operating Leases	492
Sub-lease Income	26
Net Operating Leases	466
2014
Schedule of Operating Leases [Line Items]
Operating Leases	475
Sub-lease Income	22
Net Operating Leases	453
2015
Schedule of Operating Leases [Line Items]
Operating Leases	434
Sub-lease Income	17
Net Operating Leases	417
2016
Schedule of Operating Leases [Line Items]
Operating Leases	374
Sub-lease Income	12
Net Operating Leases	362
2017
Schedule of Operating Leases [Line Items]
Operating Leases	333
Sub-lease Income	7
Net Operating Leases	326
Thereafter
Schedule of Operating Leases [Line Items]
Operating Leases	1,596
Sub-lease Income	1
Net Operating Leases	$ 1,595