Summary of Significant Accounting Policies - Identified Intangible Assets By Major Classification (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Intangible Assets Net Excluding Goodwill [Line Items]
Gross	$ 6,129	$ 5,154
Accumulated Amortization	(1,386)	(1,081)
Net Book Value	4,743	4,073	4,103
Customer Relationships [Member]
Intangible Assets Net Excluding Goodwill [Line Items]
Gross	3,522	3,044
Accumulated Amortization	(907)	(717)
Net Book Value	2,615	2,327
Trademarks [Member]
Intangible Assets Net Excluding Goodwill [Line Items]
Gross	877	716
Accumulated Amortization	(152)	(122)
Net Book Value	725	594
Trade Names [Member]
Intangible Assets Net Excluding Goodwill [Line Items]
Gross	643	643
Net Book Value	643	643
Other Finite Lived Intangible Assets [Member]
Intangible Assets Net Excluding Goodwill [Line Items]
Gross	1,087	751
Accumulated Amortization	(327)	(242)
Net Book Value	$ 760	$ 509