Investments (Distribution Of Held To Maturity Investments By Contractual Maturity) (Details) (USD $) In Millions	Sep. 30, 2011		Dec. 31, 2010
Variable Interest Entity, Primary Beneficiary [Member] | Mortgage-Backed Securities [Member] | Held-To-Maturity [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investments held-to-maturity
Fair Value
Variable Interest Entity, Primary Beneficiary [Member] | Asset-Backed Securities [Member] | Held-To-Maturity [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investments held-to-maturity	3,886
Fair Value	3,492
Variable Interest Entity, Primary Beneficiary [Member] | Held-To-Maturity [Member]
Schedule of Held-to-maturity Securities [Line Items]
Due after five years through ten years, Amortized Cost
Due after five years through ten years, Fair Value
Due after ten years through fifteen years, Amortized Cost
Due after ten years through fifteen years, Fair Value
Due after fifteen years, Amortized Cost
Due after fifteen years, Fair Value
Amortized Cost	3,886
Fair Value	3,492
Mortgage-Backed Securities [Member] | Held-To-Maturity [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investments held-to-maturity
Fair Value
Held-To-Maturity [Member]
Schedule of Held-to-maturity Securities [Line Items]
Due after one year through five years, Amortized Cost	1	[1]
Due after one year through five years, Fair Value	1	[1]
Due after five years through ten years, Amortized Cost
Due after five years through ten years, Fair Value
Due after ten years through fifteen years, Amortized Cost
Due after ten years through fifteen years, Fair Value
Due after fifteen years, Amortized Cost
Due after fifteen years, Fair Value
Amortized Cost	1
Fair Value	1
Variable Interest Entity, Primary Beneficiary [Member]
Schedule of Held-to-maturity Securities [Line Items]
Investments held-to-maturity	3,886		4,039
Fair Value	$ 3,492		$ 3,760

[1] Relates to tax credit investments reported in "Other investments" on the Company's consolidated balance sheets.