Exit and Disposal Costs - Components of and Changes in Restructuring Accruals (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Restructuring Cost And Reserve [Line Items]
Balance at ending of period	$ 164
Employee Severance [Member]
Restructuring Cost And Reserve [Line Items]
Balance at beginning of period	171
Provision	77
Payments	(112)
Balance at ending of period	136
Facility and Other Exit Costs [Member]
Restructuring Cost And Reserve [Line Items]
Balance at beginning of period	118
Provision	44
Payments	(134)
Balance at ending of period	28
Continuing Operations [Member] | Exploration and Production [Member]
Restructuring Cost And Reserve [Line Items]
Balance at ending of period	20
Continuing Operations [Member] | Exploration and Production [Member] | Employee Severance [Member]
Restructuring Cost And Reserve [Line Items]
Balance at beginning of period	32
Provision	19
Payments	(32)
Balance at ending of period	19
Continuing Operations [Member] | Exploration and Production [Member] | Facility and Other Exit Costs [Member]
Restructuring Cost And Reserve [Line Items]
Balance at beginning of period	53
Provision	(16)
Payments	(36)
Balance at ending of period	1
Continuing Operations [Member] | Corporate and Other [Member]
Restructuring Cost And Reserve [Line Items]
Balance at ending of period	47
Continuing Operations [Member] | Corporate and Other [Member] | Employee Severance [Member]
Restructuring Cost And Reserve [Line Items]
Balance at beginning of period	32
Provision	17
Payments	(20)
Balance at ending of period	29
Continuing Operations [Member] | Corporate and Other [Member] | Facility and Other Exit Costs [Member]
Restructuring Cost And Reserve [Line Items]
Balance at beginning of period	17
Provision	13
Payments	(12)
Balance at ending of period	18
Discontinued Operations [Member]
Restructuring Cost And Reserve [Line Items]
Balance at ending of period	97
Discontinued Operations [Member] | Employee Severance [Member]
Restructuring Cost And Reserve [Line Items]
Balance at beginning of period	107
Provision	41
Payments	(60)
Balance at ending of period	88
Discontinued Operations [Member] | Facility and Other Exit Costs [Member]
Restructuring Cost And Reserve [Line Items]
Balance at beginning of period	48
Provision	47
Payments	(86)
Balance at ending of period	$ 9