Goodwill and Other Intangible Assets (Intangible Assets Subject to Amortization) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 5,520	$ 5,772
Accumulated amortization	(4,226)	(4,226)
Net	1,294	1,546
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	353	391
Increase (Decrease) in Intangible Assets, Current	182
Amortization of intangible assets	450	566	653
2013	420
2014	299
2015	231
2016	176
2017	124
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,227	1,186
Accumulated amortization	(808)	(697)
Net	419	489
Finite Lived Intangible Assets, Useful Life Average	7.0
Other Finite-Lived Intangible Assets, Gross	33
Patents, Licenses And Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	191	250
Accumulated amortization	(160)	(208)
Net	31	42
Computer Software, Intangible Asset [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	2,126	2,048
Accumulated amortization	(1,681)	(1,597)
Net	445	451
Finite Lived Intangible Assets, Useful Life Average	4.2
Other Finite-Lived Intangible Assets, Gross	143
Leases, Acquired-in-Place [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,163	1,470
Accumulated amortization	(792)	(944)
Net	371	526
Present Value Of Future Profits [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	530	491
Accumulated amortization	(530)	(491)
Net	0	0
All Other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	283	327
Accumulated amortization	(255)	(289)
Net	28	38
Finite Lived Intangible Assets, Useful Life Average	6.7
Other Finite-Lived Intangible Assets, Gross	$ 6