Restructuring and Asset Related Charges - Net - 2015 Plan (Details) $ in Millions	3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) employees	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) employees	Dec. 31, 2015 USD ($) employees
Restructuring Cost and Reserve [Line Items]
Restructuring, Settlement and Impairment Provisions	$ 139	$ 0		$ 126	$ 452
2015 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Number of Positions Eliminated | employees							2,250
Employee Severance [Member] | 2015 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment	0	0	$ (9)	(9)	0
Restructuring, Settlement and Impairment Provisions							$ 235
Payments for Restructuring			33			$ 190
Restructuring Reserve			$ 3			$ 45
Restructuring And Related Cost, Number Of Remaining Positions To Be Eliminated | employees			40			290
Impairment of Long-Lived Assets and Other Assets [Member] | 2015 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment	0	(1)		0	(3)
Costs Associated with Exit and Disposal Activities [Member] | 2015 Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment	$ 0	$ 1		$ (1)	$ 6