Guarantees (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Guarantor Obligations [Line Items]
Service and product warranties and product performance guarantees - beginning of year	$ 1,360	$ 1,332
Warranties and performance guarantees issued	79	94
Settlements made	(71)	(76)
Product warranty accrual - other	(39)	(14)
Service and product warranties and product performance guarantees - end of period	1,329	1,336
Performance Guarantee [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 97