Business Acquisitions (Summary of Estimated Fair Value and Useful Lives of Intangible Assets) (Details) (OptionsXpress Holdings, Inc. [Member], USD $) In Millions, unless otherwise specified	0 Months Ended
	Sep. 01, 2011
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 285
Customer relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value	200
Estimated Useful Life (In Years)	11 years
Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value	70
Estimated Useful Life (In Years)	9 years
Trade name [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 15
Estimated Useful Life (In Years)	9 years