Significant Accounting Policies (Details Textuals) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Significant Accounting Policies [Line Items]
Other Nonoperating Income	$ 40	$ 46	$ 81	$ 90
Effective Income Tax Rate, Continuing Operations	28.00%	29.00%	31.00%	30.00%
Other Information Pertaining to Income Taxes			The 1% decrease in the effective tax rate for the three months ended June 30, 2014 is due to higher production tax credits. The 1% increase in effective tax rate for the six months ended June 30, 2014 is due to $8 million of deferred tax expense resulting from New York state income tax reform enacted on March 31, 2014, partially offset by higher production tax credits.
Unrecognized Tax Benefits that would impact Effective Tax Rate	2		2
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Amount of Unrecognized Benefit	1		1
Minimum [Member]
Significant Accounting Policies [Line Items]
Finite Lived Asset Useful Life			1 year
Maximum [Member]
Significant Accounting Policies [Line Items]
Finite Lived Asset Useful Life			28 years
Power and Industrial Projects [Member]
Significant Accounting Policies [Line Items]
Other Nonoperating Income	$ 15	$ 20	$ 32	$ 35