Contingencies and Commitments (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014 agreement
Guarantees Letters Of Credit [Abstract]
The range of expiration dates of guarantees made by the Parent Company	less than one year to more than 20 years
Lower limit of expiration dates of guarantees (less than one year)	1 year
Upper limit of expiration dates of guarantees (more than 20 years)	19 years
Obligations made by the Parent Company associated with non-recourse debt	$ 24
Contingent Contractual Obligations [Line Items]
Amount	723
Number of Agreements	34
Guarantees and commitments
Contingent Contractual Obligations [Line Items]
Amount	333
Number of Agreements	16
Maximum Exposure Range for Each Agreement	<$1 - 53
Maximum exposure range, lower limit (less than $1)	1
Maximum exposure range, upper limit	53
Asset sale related indemnities
Contingent Contractual Obligations [Line Items]
Amount	287
Number of Agreements	5
Maximum Exposure Range for Each Agreement	$2 - 209
Maximum exposure range, lower limit (less than $1)	2
Maximum exposure range, upper limit	209
Cash collateralized letters of credit
Contingent Contractual Obligations [Line Items]
Amount	102
Number of Agreements	11
Maximum Exposure Range for Each Agreement	<$1 - 63
Maximum exposure range, lower limit (less than $1)	1
Maximum exposure range, upper limit	63
Letters of credit under the senior secured credit facility
Contingent Contractual Obligations [Line Items]
Amount	1
Number of Agreements	2
Maximum Exposure Range for Each Agreement	<$1
Maximum exposure range, lower limit (less than $1)	$ 1
Letters of credit under the senior secured credit facility | Minimum [Member]
Contingent Contractual Obligations [Line Items]
Letter of credit fee percentage paid	0.20%
Letters of credit under the senior secured credit facility | Maximum [Member]
Contingent Contractual Obligations [Line Items]
Letter of credit fee percentage paid	2.50%