Schedule II Valuation and Qualiying Accounts (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Valuation allowance - deferred tax assets
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, balance at beginning of period	$ 2,968		$ 3,393		$ 3,132
Valuation allowances and reserves, charged (credited) to income	(2,253)		(206)		60
Valuation allowances and reserves, charged (credited) to AOCL	(32)		(234)		191
Valuation allowances and reserves, deductions from reserves	0		0		(4)
Valuation allowances and reserves, translation adjustment during period	(51)		15		14
Valuation allowances and reserves, balance at end of period	632		2,968		3,393
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation allowances and reserves, balance at beginning of period	99		99		97
Valuation allowances and reserves, charged (credited) to income	19		18		20
Valuation allowances and reserves, charged (credited) to AOCL	0		0		0
Valuation allowances and reserves, deductions from reserves	(39)	[1]	(20)	[1]	(20)	[1]
Valuation allowances and reserves, translation adjustment during period	10		2		2
Valuation allowances and reserves, balance at end of period	$ 89		$ 99		$ 99

[1] Note: (a) Accounts receivable charged off.