Segment Information - Schedule of Segment Reporting Information, by Segment (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
Segment Reporting Information [Line Items]
Interest expense included in the segment results	$ 90	$ 98	$ 193	$ 197
Interest Income Excluded From Segment Information
Segment Reporting Information [Line Items]
Interest income included in the segment results	5	2	10	2
Interest Expense Excluded From Segment Information
Segment Reporting Information [Line Items]
Interest expense included in the segment results	$ 4	$ 6	$ 10	$ 12