Basis of Presentation (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Total revenues	$ 4,525	$ 4,612	$ 9,038	$ 9,222
Total operating expenses	3,810	3,955	7,541	7,911
Restatement adjustment
Total revenues			0
Total operating expenses			0
Net income			$ 0