Benefit Plans (Accumulated Benefit Obligation) (Details) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
U.S. Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation		$ 1,167	$ 1,150
Information for pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation		1,188	1,172
Accumulated benefit obligation		1,167	1,150
Fair value of plan assets		1,044	1,021
Information for pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation		1,188	1,172
Fair value of plan assets		1,044	1,021
Foreign Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation		3,942	2,836
Information for pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation		3,671	2,585
Accumulated benefit obligation		3,638	2,561
Fair value of plan assets		2,448	1,842
Information for pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation	[1]	3,793	2,600
Fair value of plan assets	[1]	2,565	1,853
Electropaulo | Foreign Defined Benefit Plans
Information for pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation		$ 1,200	$ 686

[1] $1.2 billion and $686 million of the total net unfunded projected benefit obligation is due to Eletropaulo in Brazil as of December 31, 2016 and 2015, respectively.