Segment Information - Schedule of Segment Reporting Information, by Segment (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]
Interest expense included in the segment results	$ 103	$ 98
Interest Income Excluded From Segment Information
Segment Reporting Information [Line Items]
Interest income included in the segment results	5	0
Interest Expense Excluded From Segment Information
Segment Reporting Information [Line Items]
Interest expense included in the segment results	$ 6	$ 5