Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation and Qualifying Accounts Beginning Balance		$ 192	$ 213	$ 260
Additions charged to bad debt provision	[1]	37	49	49
Amounts (credited) charged to other income statement accounts	[1]	6	5	1
Deductions and other, net of recoveries	[2]	(61)	(75)	(97)
Valuation and Qualifying Accounts Ending Balance		174	192	213
Accounts Receivable [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation and Qualifying Accounts Beginning Balance		74	82	106
Additions charged to bad debt provision	[1]	13	21	16
Amounts (credited) charged to other income statement accounts	[1]	2	5	(2)
Deductions and other, net of recoveries	[2]	(25)	(34)	(38)
Valuation and Qualifying Accounts Ending Balance		64	74	82
Financing Receivable [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation and Qualifying Accounts Beginning Balance		118	131	154
Additions charged to bad debt provision	[1]	24	28	33
Amounts (credited) charged to other income statement accounts	[1]	4	0	3
Deductions and other, net of recoveries	[2]	(36)	(41)	(59)
Valuation and Qualifying Accounts Ending Balance		$ 110	$ 118	$ 131

[1] Bad debt provisions relate to estimated losses due to credit and similar collectability issues. Other charges (credits) relate to adjustments to reserves necessary to reflect events of non-payment such as customer accommodations and contract terminations.

[2] Deductions and other, net of recoveries primarily relates to receivable write-offs, but also includes the impact of foreign currency translation adjustments and recoveries of previously written off receivables.