Benefit Plans (Accumulated Benefit Obligation) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
U.S. Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	$ 1,036		$ 1,180
Information for pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	1,059		1,210
Accumulated benefit obligation	1,036		1,180
Fair value of plan assets	941		883
Information for pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation	1,059		1,210
Fair value of plan assets	941		883
Foreign Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	4,686		6,662
Information for pension plans with an accumulated benefit obligation in excess of plan assets:
Projected benefit obligation	4,412		6,398
Accumulated benefit obligation	4,366		6,319
Fair value of plan assets	3,246		4,360
Information for pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation	4,425	[1]	6,768
Fair value of plan assets	3,259	[1]	4,712
Electropaulo | Foreign Defined Benefit Plans
Information for pension plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation	$ 1,100

[1] $1.1 billion of the total net unfunded projected benefit obligation is due to Eletropaulo in Brazil.