Pension and Other Benefit Plans - Changes in Projected Benefit Obligation, Plan Assets and Funded Status of Plans (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Amounts Recognized in Balance Sheet
Postretirement Benefits	$ (1,501)	$ (670)
US Plan Assets
Change in Projected Benefit Obligations
Projected benefit obligation at beginning of year	3,418	3,558
Service cost	72	80	68
Interest cost	164	150	152
Actuarial losses (gains)	627	(232)
Benefits paid	(144)	(138)
Projected benefit obligation at end of year	4,137	3,418	3,558
Change in Plan Assets
Plan assets at fair value at beginning of year	3,269	2,910
Actual return on plan assets	339	356
Company contributions	85	141
Benefits paid	(144)	(138)
Plan assets at fair value at end of year	3,549	3,269	2,910
(Unfunded Liability) / Asset	(588)	(149)
Amounts Recognized in Balance Sheet
Postretirement Benefits	(588)	(149)
Total of post retirement benefits	(588)	(149)
Amounts Recognized in Accumulated Other Comprehensive Loss
Actuarial (gains) losses	1,104	687
Prior service cost	66	78
Total amount recognized in accumulated other comprehensive income	1,170	765
Accumulated benefit obligation	3,805	3,158
International
Change in Projected Benefit Obligations
Projected benefit obligation at beginning of year	5,981	5,798
Service cost	126	127	86
Interest cost	288	253	241
Contributions by plan participants	122	104
Actuarial losses (gains)	1,000	(168)
Currency effect	(90)	30
Benefits paid	(178)	(163)
Projected benefit obligation at end of year	7,249	5,981	5,798
Change in Plan Assets
Plan assets at fair value at beginning of year	6,246	5,120
Actual return on plan assets	502	836
Currency effect	(102)	35
Company contributions	240	314
Contributions by plan participants	122	104
Benefits paid	(178)	(163)
Plan assets at fair value at end of year	6,830	6,246	5,120
(Unfunded Liability) / Asset	(419)	265
Amounts Recognized in Balance Sheet
Postretirement Benefits	(546)	(5)
Other Assets	127	270
Total of post retirement benefits	(419)	265
Amounts Recognized in Accumulated Other Comprehensive Loss
Actuarial (gains) losses	1,658	882
Prior service cost	357	418
Total amount recognized in accumulated other comprehensive income	2,015	1,300
Accumulated benefit obligation	$ 6,793	$ 5,593