Schedule II - Valuation and Qualifying Accounts and Allowances (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
of Period		$ 113	$ 108	$ 106
Expense		69	48	32
Additions		0	1	4
Reductions (a) (b)		(53)	(42)	(26)	[1]
Period		129	113	108
Valuation allowance on deferred tax assets [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
of Period		868	732	554
Expense		872	159	222
Additions		0	0	0
Reductions (a) (b)	[2]	(2)	(23)	(44)
Period		$ 1,738	$ 868	$ 732

[1] Includes write-offs and amounts reclassified to assets held for sale.

[2] Other reductions for valuation allowance on deferred taxes primarily due to currency translation.