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Fair Value Of Financial Instruments (Aggregate Fair Value And Remaining Contractual Principal Balance Outstanding On Fair Value Option) (Detail) - USD ($) $ in Millions | Dec. 31, 2015 | Dec. 31, 2014
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Non Variable Interest Entity [Member] |  |
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items] |  |
Medium-term notes, contractual outstanding principal | $ 217 | $ 242
Medium-term notes, fair value | 161 | 197
Medium-term notes, difference | 56 | 45
Variable Interest Entity [Member] |  |
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items] |  |
Loans receivable, contractual outstanding principal | 1,619 | 2,502
Variable interest entity notes, contractual outstanding principal | 3,663 | 3,584
Loans receivable, fair value | 1,292 | 2,142
Variable interest entity notes, fair value | 2,362 | 2,479
Loans receivable, difference | 327 | 360
Variable interest entity notes, difference | 1,301 | 1,105
Residential Mortgage Loans [Member] | Variable Interest Entity [Member] |  |
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items] |  |
Loans receivable, contractual outstanding principal | 1,260 | 1,554
Loans receivable, 90 days or more past due, contractual outstanding principal | 177 | 227
Loans receivable, fair value | 1,149 | 1,377
Loans receivable, 90 days or more past due, fair value | 36 | 54
Loans receivable, difference | 111 | 177
Loans receivable, 90 days or more past due, difference | 141 | 173
Other Loans [Member] | Variable Interest Entity [Member] |  |
Schedule Of Fair Value Of Separate Accounts By Major Category Of Investment [Line Items] |  |
Loans receivable, contractual outstanding principal | 107 | 721
Loans receivable, 90 days or more past due, contractual outstanding principal | 75 |
Loans receivable, fair value | 107 | 711
Loans receivable, difference | 0 | $ 10
Loans receivable, 90 days or more past due, difference | $ 75 |

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- Definition This item represents the difference between the aggregate fair value and the aggregate unpaid principal balance of loans and long-term receivables (other than securities categorized as trading, available-for-sale or held-to-maturity) that have contractual principal amounts and for which the fair value option has been elected. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 28 -Subparagraph (d)(1) -URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612 + Details
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- Definition This item represents the aggregate fair value of loans held as assets that are 90 days or more past due for which the fair value option has been elected. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 28 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612 + Details
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- Definition For loans held as assets for which the fair value option has been elected, this item represents the difference between the aggregate fair value and the aggregate unpaid principal balance of those loans that are 90 days or more past due. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 28 -Subparagraph (e)(3) -URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612 + Details
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