Debt and Equity Transactions (Unaudited) Interest, Dividends and Maturities (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Long-term Debt, Fiscal Year Maturity [Abstract]
Remainder of 2013	$ 70,000,000		$ 70,000,000
2014	616,000,000		616,000,000
2015	1,100,000,000		1,100,000,000
2016	750,000,000		750,000,000
2017	727,000,000		727,000,000
Thereafter	18,000,000,000		18,000,000,000
Interest costs incurred	167,000,000	55,000,000	242,000,000	154,000,000
Interest costs capitalized	$ 35,000,000	$ 12,000,000	$ 53,000,000	$ 48,000,000
Supplemental Dividend [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Dividends Payable, Date Declared	May 31, 2013
Dividends Payable, Amount Per Share (in dollars per share)	$ 1.00		$ 1.00
Dividends Payable, Date to be Paid	Jul. 01, 2013
Dividends Payable, Date of Record	Jun. 14, 2013
Quarterly Dividend [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Dividends Payable, Date Declared	Jun. 27, 2013
Dividends Payable, Amount Per Share (in dollars per share)	$ 0.3125		$ 0.3125
Dividends Payable, Date to be Paid	Aug. 01, 2013
Dividends Payable, Date of Record	Jul. 15, 2013