Restructuring and Transformation Charges (Restructuring Liability) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	$ 60
Other Restructuring | Eastern Hemisphere
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	26
Other Restructuring | Western Hemisphere
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	16
Other Restructuring | Corporate, Non-Segment [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	18
Severance and Other Restructuring Liabilities [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	61
Restructuring Charges	25
Cash Payments	(26)
Other	0
Accrued balance at end of period	60
Transformation Plan [Member] | Employee Severance
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	0
Restructuring Charges	11
Cash Payments	(8)
Other	1
Accrued balance at end of period	4
Transformation Plan [Member] | Employee Severance | Eastern Hemisphere
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	2
Transformation Plan [Member] | Employee Severance | Western Hemisphere
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Transformation Plan [Member] | Employee Severance | Corporate, Non-Segment [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	2
Transformation Plan [Member] | Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	0
Restructuring Charges	14
Cash Payments	(6)
Other	(1)
Accrued balance at end of period	7
Transformation Plan [Member] | Other Restructuring | Eastern Hemisphere
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	1
Transformation Plan [Member] | Other Restructuring | Western Hemisphere
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	0
Transformation Plan [Member] | Other Restructuring | Corporate, Non-Segment [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	6
2016-17 and Prior Plan [Member] | Employee Severance
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	21
Restructuring Charges	0
Cash Payments	(7)
Other	1
Accrued balance at end of period	15
2016-17 and Prior Plan [Member] | Employee Severance | Eastern Hemisphere
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	3
2016-17 and Prior Plan [Member] | Employee Severance | Western Hemisphere
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	2
2016-17 and Prior Plan [Member] | Employee Severance | Corporate, Non-Segment [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	10
2016-17 and Prior Plan [Member] | Other Restructuring
Restructuring Reserve [Roll Forward]
Accrued balance at beginning of period	40
Restructuring Charges	0
Cash Payments	(5)
Other	(1)
Accrued balance at end of period	34
2016-17 and Prior Plan [Member] | Other Restructuring | Eastern Hemisphere
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	20
2016-17 and Prior Plan [Member] | Other Restructuring | Western Hemisphere
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	14
2016-17 and Prior Plan [Member] | Other Restructuring | Corporate, Non-Segment [Member]
Restructuring Reserve [Roll Forward]
Accrued balance at end of period	$ 0