Derivative Financial Instruments (Summary Of Aggregate Contractual Or Notional Amounts And Gross Estimated Fair Values Related To Derivative Financial Instruments) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
With Hedge Designation [Member] | Interest Rate Risk, Interest Rate Swaps [Member]
Derivative [Line Items]
Contractual/Notional Amount	$ 300	$ 300
Estimated Fair Value, Asset	3	3
Estimated Fair Value, (Liability)	(4)	(3)
With Hedge Designation [Member] | Commodities, Forwards - Short [Member]
Derivative [Line Items]
Contractual/Notional Amount	269	268
Estimated Fair Value, Asset	71	64
Estimated Fair Value, (Liability)	(11)	(22)
With Hedge Designation [Member] | Foreign Exchange, Currency Forwards - Short [Member]
Derivative [Line Items]
Contractual/Notional Amount	65	154
Estimated Fair Value, Asset	2	1
Estimated Fair Value, (Liability)	(1)	(8)
Without Hedge Designation [Member] | Interest Rate Risk, Interest Rate Swaps [Member]
Derivative [Line Items]
Contractual/Notional Amount	117	100
Estimated Fair Value, Asset	1	1
Estimated Fair Value, (Liability)	(1)	(1)
Without Hedge Designation [Member] | Equity Markets, Options - Purchased [Member]
Derivative [Line Items]
Contractual/Notional Amount	650	286
Estimated Fair Value, Asset	27	33
Without Hedge Designation [Member] | Equity Markets, Equity Options - Written [Member]
Derivative [Line Items]
Contractual/Notional Amount	389	398
Estimated Fair Value, (Liability)	(13)	(23)
Without Hedge Designation [Member] | Equity Swaps And Warrants - Long [Member]
Derivative [Line Items]
Contractual/Notional Amount	20	63
Estimated Fair Value, Asset	14	16
Without Hedge Designation [Member] | Interest Rate Risk, Credit Default Swaps - Purchased Protection [Member]
Derivative [Line Items]
Contractual/Notional Amount	58	145
Estimated Fair Value, Asset		8
Estimated Fair Value, (Liability)	(1)	(1)
Without Hedge Designation [Member] | Interest Rate Risk, Credit Default Swaps - Sold Protection [Member]
Derivative [Line Items]
Contractual/Notional Amount	38	28
Estimated Fair Value, (Liability)		(2)
Without Hedge Designation [Member] | Foreign Exchange, Currency Forwards - Long [Member]
Derivative [Line Items]
Contractual/Notional Amount	180	203
Estimated Fair Value, Asset		4
Estimated Fair Value, (Liability)	(2)
Without Hedge Designation [Member] | Foreign Exchange, Currency Forwards - Short [Member]
Derivative [Line Items]
Contractual/Notional Amount	142	330
Estimated Fair Value, (Liability)		$ (2)