Goodwill and Other Intangible Assets (Intangible Assets Subject to Amortization) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 5,461		$ 5,520
Accumulated amortization	(4,150)		(4,226)
Net	1,311		1,294
Adjustments To Reflect Present Value Of Future Profits In Run Off Insurance Operations To Reflect Effects That Would Have Been Recognized Had Related Unrealized Investment Securities Holding Gains Loses Actually Been Realized	344		353
Amortization expense	108	110
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,207		1,227
Accumulated amortization	(802)		(808)
Net	405		419
Patents, Licenses And Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	190		191
Accumulated amortization	(160)		(160)
Net	30		31
Computer Software, Intangible Asset [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	2,200		2,126
Accumulated amortization	(1,705)		(1,681)
Net	495		445
Leases, Acquired-in-Place [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,027		1,163
Accumulated amortization	(690)		(792)
Net	337		371
Present Value Of Future Profits [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	539		530
Accumulated amortization	(539)		(530)
Net	0		0
All Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	298		283
Accumulated amortization	(254)		(255)
Net	$ 44		$ 28