Accumulated Other Comprehensive Income - Component of Accumulated Other Comprehensive Income (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), tax	$ (4)	$ 10	$ (7)	$ 10
Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), tax			(7)
Amounts reclassified from accumulated other comprehensive income, tax			6
Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), tax			1
Amounts reclassified from accumulated other comprehensive income, tax			0
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), tax			0
Amounts reclassified from accumulated other comprehensive income, tax			0
Post - Retirement Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), tax			0
Amounts reclassified from accumulated other comprehensive income, tax			$ 0