Shareowners' Equity (Parenthetical) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended				12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Sep. 30, 2012 First Preferred Shares Issuance [Member]	Dec. 31, 2012 Second Preferred Shares Issuance [Member]	Jun. 30, 2013 Second Preferred Shares Issuance [Member]
Noncontrolling Interest [Line Items]
Preferred Stock, Shares Issued	50,000		50,000		40,000	22,500	17,500	10,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01		$ 0.01		$ 0.01
Proceeds From Issuance Of Preferred Stock	$ 990		$ 990	$ 2,227			$ 3,960
Initial Fixed Interest Rate Of Preferred Stock	5.25%		5.25%			7.125%	6.25%
Percentage Points Over Three Month LIBOR	2.967%		2.967%			5.296%	4.704%
Dividend Amount Paid To Parent	447	475
Special Dividend Paid To Parent			$ 1,500	$ 2,525