2.2.0.25falsefalse40604 - Disclosure - Investment Securities (Carrying value, Gross Unrecorded Gains and Fair Value of Held-to-Maturity Investment Securities) (Details)truefalseIn Millionsfalse1falsefalseUSDfalsefalse12/31/2010
USD ($)
USD ($) / shares
$As_Of_12_31_2010http://www.sec.gov/CIK0001141391instant2010-12-31T00:00:000001-01-01T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit13Standardhttp://www.xbrl.org/2003/instancepurexbrli0Unit16Dividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2falsefalseUSDfalsefalse12/31/2009
USD ($)
USD ($) / shares
$As_Of_12_31_2009http://www.sec.gov/CIK0001141391instant2009-12-31T00:00:000001-01-01T00:00:00Unit12Standardhttp://www.xbrl.org/2003/iso4217USDiso42170Unit1Standardhttp://www.xbrl.org/2003/instancesharesxbrli0Unit16Divide
http://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0Unit13Standardhttp://www.xbrl.org/2003/instancepurexbrli0USDUSD$2true0us-gaap_MarketableSecuritiesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsef
alsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalse3false0us-gaap
_HeldToMaturitySecuritiesDebtMaturitiesNetCarryingAmountus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse336000000336falsetruefalsefalsefalse2truefalsefalse338000000338falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis item represents the total of all debt securities grouped by maturity dates, at cost, net of ad
justments made for accretion, amortization, other-than-temporary impairments, and hedging, if any, which are classified as held-to-maturity.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 20
falsefalse4false0ma_HeldToMaturitySecuritiesUnrecognizedGainsmafalsecreditinstantAs of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse20000002falsefalsefalsefalsefalse2truefalsefalse20000002falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAs of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.No authoritative reference available.falsefalse5false0us-gaap_HeldToMaturitySecuritiesFairValueus-gaaptruedebitinst
antNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse338000000338falsetruefalsefalsefalse2truefalsefalse340000000340falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThis item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 19
Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 137
truefalse24Investment Securities (Carrying value, Gross Unrecorded Gains and Fair Value of Held-to-Maturity Investment Securities) (Details) (USD $)MillionsUnKnownUnKnownUnKnownfalsetrue
