Income Tax - Additional Information (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	Dec. 31, 2013
Income Tax Examination [Line Items]
Pretax provision relating to accounts receivable		$ 664		$ 572
Deferred tax assets, valuation allowances relating to net operating losses in certain countries	246		246		238
US federal statutory rate	35.00%	35.00%	35.00%	35.00%
Domestic Country
Income Tax Examination [Line Items]
Pretax provision relating to accounts receivable		53		53
Foreign Country
Income Tax Examination [Line Items]
Pretax provision relating to accounts receivable		$ 717		$ 625