Derivative Instruments and Hedging Activities - Part 1 (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Foreign Exchange Contract [Member]
Derivative Tables [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	$ 231	$ 290	$ 255	$ 277
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	(16)	47
Fair Value Measurements With Unobservable Inputs Reconciliation Recurring Basis Regulatory Assets Liabilities
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements	(8)	(1)
Derivative Liability, Fair Value, Gross Liability	48		64
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Period Increase (Decrease)	(24)	45
Interest Rate Contract [Member]
Derivative Tables [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	(183)	(416)	(179)	(304)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	0	3
Fair Value Measurements With Unobservable Inputs Reconciliation Recurring Basis Regulatory Assets Liabilities
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements	10	18
Derivative Liability, Fair Value, Gross Liability	301		300
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Period Increase (Decrease)	2	4
Interest Rate Contract [Member] | Libor and Euribor [Member]
Derivative Tables [Line Items]
Derivatives, notional amount	4,834
Cross currency derivatives [Member]
Derivative Tables [Line Items]
Derivative Liability, Fair Value, Gross Liability	10		18
Commodity Contract [Member]
Derivative Tables [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	2	0	5	3
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	0	0
Fair Value Measurements With Unobservable Inputs Reconciliation Recurring Basis Regulatory Assets Liabilities
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements	(3)	(3)
Derivative Liability, Fair Value, Gross Liability	28		42
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Period Increase (Decrease)	0	0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	50	(126)	81	$ (24)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings	(16)	50
Fair Value Measurements With Unobservable Inputs Reconciliation Recurring Basis Regulatory Assets Liabilities		0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements	(1)	14
Derivative Liability, Fair Value, Gross Liability	387		$ 424
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Period Increase (Decrease)	(22)	49
Unidad de Fomento (funds code) | Foreign Exchange Contract [Member]
Derivative Tables [Line Items]
Derivatives, notional amount	329
Unidad de Fomento (funds code) | Cross currency derivatives [Member]
Derivative Tables [Line Items]
Derivatives, notional amount	378
Euro EUR [Member] | Foreign Exchange Contract [Member]
Derivative Tables [Line Items]
Derivatives, notional amount	159
Argentina, Pesos | Foreign Exchange Contract [Member]
Derivative Tables [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	231
Derivatives, notional amount	172
Other unspecified currency [Domain] | Foreign Exchange Contract [Member]
Derivative Tables [Line Items]
Derivatives, notional amount	217
Other comprehensive income - Derivative activity [Member] | Foreign Exchange Contract [Member]
Derivative Tables [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	3
Other comprehensive income - Derivative activity [Member] | Interest Rate Contract [Member]
Derivative Tables [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	(12)	(99)
Other comprehensive income - Derivative activity [Member] | Commodity Contract [Member]
Derivative Tables [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	0	0
Other comprehensive income - Derivative activity [Member]
Derivative Tables [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)	$ (12)	(96)
Other Comprehensive Income- Foreign currency translation activity [Member] | Foreign Exchange Contract [Member]
Derivative Tables [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)		(33)
Other Comprehensive Income- Foreign currency translation activity [Member] | Interest Rate Contract [Member]
Derivative Tables [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)		(3)
Other Comprehensive Income- Foreign currency translation activity [Member] | Commodity Contract [Member]
Derivative Tables [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)		0
Other Comprehensive Income- Foreign currency translation activity [Member]
Derivative Tables [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Other Comprehensive Income (Loss)		$ (36)