Investments (Select Information For Securities In A Gross Unrealized Loss Position) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Schedule Of Available For Sale Securities Residential And Commercial Mortgage At Risk [Line Items]
Amortized cost	$ 81,010	$ 79,412
Fair Value	89,621us-gaap_AvailableForSaleSecurities	87,069us-gaap_AvailableForSaleSecurities
AFS Securities Backed By Pools Of Residential Mortgages [Member]
Schedule Of Available For Sale Securities Residential And Commercial Mortgage At Risk [Line Items]
Amortized cost	1,183	1,113
Fair Value	1,127	1,050
Gross Unrealized Losses	56	63
AFS Securities Backed By Pools Of Commercial Mortgages [Member]
Schedule Of Available For Sale Securities Residential And Commercial Mortgage At Risk [Line Items]
Amortized cost	21	151
Fair Value	12	140
Gross Unrealized Losses	9	11
Total AFS Securities Backed By Pools Of Residential And Commercial Mortgages [Member]
Schedule Of Available For Sale Securities Residential And Commercial Mortgage At Risk [Line Items]
Amortized cost	1,204	1,264
Fair Value	1,139	1,190
Gross Unrealized Losses	65	74
AFS Securities Subject To Detailed Analysis Backed By Pools Of Residential Mortgages [Member]
Schedule Of Available For Sale Securities Residential And Commercial Mortgage At Risk [Line Items]
Amortized cost	982	985
Fair Value	928	924
Gross Unrealized Losses	54	61
AFS Securities Subject To Detailed Analysis Backed By Pools Of Commercial Mortgages [Member]
Schedule Of Available For Sale Securities Residential And Commercial Mortgage At Risk [Line Items]
Amortized cost	7	13
Fair Value	6	12
Gross Unrealized Losses	1	1
AFS Securities Subject To Detailed Analysis Backed By Pools Of Residential And Commercial Mortgages [Member]
Schedule Of Available For Sale Securities Residential And Commercial Mortgage At Risk [Line Items]
Amortized cost	989	998
Fair Value	934	936
Gross Unrealized Losses	$ 55	$ 62

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

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-Publisher FASB

-Name Accounting Standards Codification

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-Section 50

-Paragraph 5

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-Publisher FASB

-Name Accounting Standards Codification

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.2)

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Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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