Income Taxes - Tax Carryforwards Table (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Foreign Tax Credits [Member]
Tax Carryforwards [Line Items]
Tax credit carryforward	$ 325
Foreign Tax Credits [Member] | Minimum [Member]
Tax Carryforwards [Line Items]
Tax credit carryforward, expiration date(s)	Dec. 31, 2015
Foreign Tax Credits [Member] | Maximum [Member]
Tax Carryforwards [Line Items]
Tax credit carryforward, expiration date(s)	Dec. 31, 2023
Texas Margins Tax Credit [Member]
Tax Carryforwards [Line Items]
Tax credit carryforward	35
Tax credit carryforward, expiration date(s)	Dec. 31, 2026
Foreign [Member]
Tax Carryforwards [Line Items]
Net operating loss carryforward	1,265
Foreign [Member] | Minimum [Member]
Tax Carryforwards [Line Items]
Net operating loss carryforwards, expiration date(s)	Dec. 31, 2014
State [Member]
Tax Carryforwards [Line Items]
Net operating loss carryforward	$ 4,527
State [Member] | Minimum [Member]
Tax Carryforwards [Line Items]
Net operating loss carryforwards, expiration date(s)	Dec. 31, 2014
State [Member] | Maximum [Member]
Tax Carryforwards [Line Items]
Net operating loss carryforwards, expiration date(s)	Dec. 31, 2032