Benefit Plans (Accumulated Benefit Obligation) (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
U.S. Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation		$ 1,150	$ 1,208
Information for pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation		1,172	1,235
Accumulated benefit obligation		1,150	1,208
Fair value of plan assets		1,021	1,061
Information for pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation		1,172	1,235
Fair value of plan assets		1,021	1,061
Foreign Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation		2,931	4,301
Information for pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation		2,683	4,021
Accumulated benefit obligation		2,656	3,979
Fair value of plan assets		1,931	2,885
Information for pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation	[1]	2,697	4,038
Fair value of plan assets	[1]	1,942	2,897
Electropaulo | Foreign Defined Benefit Plans
Information for pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation		$ 700	$ 1,100

[1] (1)$686 million and $1.1 billion of the total net unfunded projected benefit obligation is due to Eletropaulo in Brazil as of December 31, 2015 and 2014, respectively.