Condensed Statements of Cash Flows (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash Flows from Operating Activities
Net Income	$ 864	$ 454	$ 787
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for deferred income taxes	52	(51)	16
Other	9	(3)	(32)
Net change in:
Receivables from brokers, dealers, and clearing organizations	220	148	202
Other securities owned	(231)	581	(290)
Other assets	(15)	133	(253)
Accrued expenses and other liabilities	(183)	289	(111)
Net cash provided by (used for) operating activities	2,464	(9)	1,437
Cash Flows from Investing Activities
Net cash used for investing activities	(8,667)	(15,410)	(14,057)
Cash Flows from Financing Activities
Issuance of long-term debt		701	747
Repayment of long-term debt	(116)	(205)	(80)
Net proceeds from common stock offering		543
Dividends paid	(295)	(288)	(279)
Proceeds from stock options exercised and other	96	35	53
Other financing activities	2	(5)	(1)
Net cash (used for) provided by financing activities	9,951	12,109	15,419
(Decrease) Increase in Cash and Cash Equivalents	3,748	(3,310)	2,799
Cash and Cash Equivalents at Beginning of Year	4,931	8,241	5,442
Cash and Cash Equivalents at End of Year	8,679	4,931	8,241
Parent Company
Cash Flows from Operating Activities
Net Income	864	454	787
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries	(591)	(478)	(253)
Provision for deferred income taxes	3	3	20
Other	1	(3)	(35)
Net change in:
Receivables from brokers, dealers, and clearing organizations		11	23
Other securities owned	6	422	(404)
Other assets	26	40	(16)
Accrued expenses and other liabilities	(76)	(2)	(1)
Net cash provided by (used for) operating activities	233	447	121
Cash Flows from Investing Activities
Due from subsidiaries - net	24	63	279
Increase in investments in subsidiaries	(366)	(1,025)	(725)
Cash payments for business combinations and investments, net of cash acquired	8	4
Net cash used for investing activities	(334)	(958)	(446)
Cash Flows from Financing Activities
Issuance of long-term debt		701	747
Repayment of long-term debt		(200)	(76)
Net proceeds from common stock offering		543
Dividends paid	(295)	(288)	(279)
Proceeds from stock options exercised and other	96	35	53
Other financing activities	3	(6)
Net cash (used for) provided by financing activities	(196)	785	445
(Decrease) Increase in Cash and Cash Equivalents	(297)	274	120
Cash and Cash Equivalents at Beginning of Year	1,149	875	755
Cash and Cash Equivalents at End of Year	$ 852	$ 1,149	$ 875