Segment Information - Revenues By Geographic Area (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Total consolidated revenues	$ 7,048	$ 6,032	$ 5,880	$ 5,479	$ 6,682	$ 5,539	$ 5,614	$ 5,387	$ 24,440	$ 23,222	$ 21,714
UNITED STATES
Segment Reporting Information [Line Items]
Total consolidated revenues									12,835	12,230	11,510
Europe, Middle East and Africa
Segment Reporting Information [Line Items]
Total consolidated revenues									6,981	6,355	5,908
Asia Pacific and Japan
Segment Reporting Information [Line Items]
Total consolidated revenues									3,191	3,193	3,017
Latin America, Mexico and Canada
Segment Reporting Information [Line Items]
Total consolidated revenues									$ 1,433	$ 1,444	$ 1,279