Common Equity Units Common Equity Units (Remarketing of Senior Debt Securities and Settlement of Stock Purchase Contracts - Narrative) (Details) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Proceeds from Issuance of Common Stock	$ 1,000,000,000	$ 0
Common Stock [Member]
Proceeds from Issuance of Common Stock	1,000,000,000
Common stock, shares issued	22,679,955
Senior Notes [Member] | Debt Remarketing Series D [Member]
Proceeds From Remarketing	$ 0
Debt Instrument, Maturity Date	Sep. 15, 2023
Debt Instrument, Interest Rate, Stated Percentage	4.368%