| Document and Entity Information | 9 Months Ended |
| Sep. 30, 2013 | |
| Entity Registrant Name | 'MERRILL LYNCH PREFERRED CAPITAL TRUST IV |
| Entity Central Index Key | '0001051830 |
| Current Fiscal Year End Date | '--12-31 |
| Entity Filer Category | 'Non-accelerated Filer |
| Document Type | '10-Q |
| Document Period End Date | 30-Sep-13 |
| Document Fiscal Year Focus | '2013 |
| Document Fiscal Period Focus | 'Q3 |
| Amendment Flag | 'false |
| Entity Common Stock, Shares Outstanding | 0 |
| Entity Well Known Seasoned Issuer | 'No |
| Entity Voluntary Filers | 'No |
| Entity Current Reporting Status | 'Yes |
| MERRILL LYNCH PREFERRED FUNDING IV, L.P. | ' |
| Entity Registrant Name | 'MERRILL LYNCH PREFERRED FUNDING IV L.P. |
| Entity Central Index Key | '0001051828 |
| Current Fiscal Year End Date | '--12-31 |
| Entity Filer Category | 'Non-accelerated Filer |
| Document Type | '10-Q |
| Document Period End Date | 30-Sep-13 |
| Document Fiscal Year Focus | '2013 |
| Document Fiscal Period Focus | 'Q3 |
| Amendment Flag | 'false |
| Entity Common Stock, Shares Outstanding | 0 |
| Entity Well Known Seasoned Issuer | 'No |
| Entity Voluntary Filers | 'No |
| Entity Current Reporting Status | 'Yes |
| Condensed Balance Sheets (USD $) | Sep. 30, 2013 | Dec. 31, 2012 |
| In Thousands, unless otherwise specified | ||
| ASSETS | ' | ' |
| Investment in affiliate partnership preferred securities | $412,372 | $412,372 |
| Total Assets | 412,372 | 412,372 |
| STOCKHOLDERS' EQUITY | ' | ' |
| Preferred securities (7.12% Trust Originated Preferred Securities; 16,000,000 authorized, issued, and outstanding; $25 liquidation amount per security) | 400,000 | 400,000 |
| Common securities (7.12% Trust Common Securities; 494,880 authorized, issued, and outstanding; $25 liquidation amount per security) | 12,372 | 12,372 |
| Total Stockholders’ Equity | $412,372 | $412,372 |
| Condensed Balance Sheets (Parenthetical) (USD $) | 9 Months Ended | 12 Months Ended |
| Sep. 30, 2013 | Dec. 31, 2012 | |
| STOCKHOLDERS' EQUITY | ' | ' |
| Preferred securities, dividend rate | 7.12% | 7.12% |
| Preferred securities, shares authorized | 16,000,000 | 16,000,000 |
| Preferred securities, shares issued | 16,000,000 | 16,000,000 |
| Preferred securities, shares outstanding | 16,000,000 | 16,000,000 |
| Preferred securities, liquidation amount per security | $25 | $25 |
| Common securities, dividend rate | 7.12% | 7.12% |
| Common securities, shares authorized | 494,880 | 494,880 |
| Common securities, shares issued | 494,880 | 494,880 |
| Common securities, shares outstanding | 494,880 | 494,880 |
| Common securities, liquidation amount per security | $25 | $25 |
| Condensed Statements of Earnings (USD $) | 3 Months Ended | 9 Months Ended | ||
| In Thousands, unless otherwise specified | Sep. 30, 2013 | Sep. 30, 2012 | Sep. 30, 2013 | Sep. 30, 2012 |
| EARNINGS | ' | ' | ' | ' |
| Earnings | $7,341 | $7,341 | $22,021 | $22,021 |
| Condensed Statements of Changes in Stockholders' Equity (USD $) | Total | PREFERRED SECURITIES | COMMON SECURITIES | UNDISTRIBUTED EARNINGS |
| In Thousands, unless otherwise specified | ||||
| Balance, beginning of period at Dec. 31, 2011 | ' | $400,000 | $12,372 | $0 |
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | ' | ' | ' | ' |
| Earnings | 22,021 | ' | ' | 22,021 |
| Distributions | ' | ' | ' | -14,680 |
| Distributions payable | ' | ' | ' | -7,341 |
| Balance, end of period at Sep. 30, 2012 | 412,372 | 400,000 | 12,372 | 0 |
| Balance, beginning of period at Dec. 31, 2012 | 412,372 | 400,000 | 12,372 | 0 |
| Increase (Decrease) in Stockholders' Equity [Roll Forward] | ' | ' | ' | ' |
| Earnings | 22,021 | ' | ' | 22,021 |
| Distributions | ' | ' | ' | -22,021 |
| Distributions payable | ' | ' | ' | 0 |
| Balance, end of period at Sep. 30, 2013 | $412,372 | $400,000 | $12,372 | $0 |
| Condensed Statements of Cash Flows (USD $) | 9 Months Ended | |
| In Thousands, unless otherwise specified | Sep. 30, 2013 | Sep. 30, 2012 |
| CASH FLOWS FROM OPERATING ACTIVITIES: | ' | ' |
| Earnings | $22,021 | $22,021 |
| Change in interest receivable from affiliate | 0 | -7,341 |
| Cash provided by operating activities | 22,021 | 14,680 |
| CASH FLOWS FROM FINANCING ACTIVITIES: | ' | ' |
| Distributions | -22,021 | -14,680 |
| Cash used for financing activities | -22,021 | -14,680 |
| NET CHANGE IN CASH | 0 | 0 |
| CASH, BEGINNING OF PERIOD | 0 | 0 |
| CASH, END OF PERIOD | $0 | $0 |
| Condensed Statements of Cash Flows (Parenthetical) (USD $) | Sep. 30, 2012 |
| In Thousands, unless otherwise specified | |
| Statement of Cash Flows [Abstract] | ' |
| Distributions payable | $7,341 |
| Condensed Balance Sheets (LP) (USD $) | Sep. 30, 2013 | Dec. 31, 2012 |
| In Thousands, unless otherwise specified | ||
| Investments: | ' | ' |
| Total Assets | $412,372 | $412,372 |
| MERRILL LYNCH PREFERRED FUNDING IV, L.P. | ' | ' |
| Investments: | ' | ' |
| Affiliate debentures | 480,292 | 480,292 |
| U.S. Government and agencies | 4,851 | 4,854 |
| Total investments | 485,143 | 485,146 |
| Total Assets | 485,143 | 485,146 |
| PARTNERS' CAPITAL | ' | ' |
| Limited partnership interest | 412,372 | 412,372 |
| General partnership interest | 72,771 | 72,774 |
| Total Partners' Capital | $485,143 | $485,146 |
| Condensed Statements of Earnings (LP) (USD $) | 3 Months Ended | 9 Months Ended | ||
| In Thousands, unless otherwise specified | Sep. 30, 2013 | Sep. 30, 2012 | Sep. 30, 2013 | Sep. 30, 2012 |
| Interest income: | ' | ' | ' | ' |
| Earnings | $7,341 | $7,341 | $22,021 | $22,021 |
| MERRILL LYNCH PREFERRED FUNDING IV, L.P. | ' | ' | ' | ' |
| Interest income: | ' | ' | ' | ' |
| Affiliate debentures | 8,550 | 8,550 | 25,648 | 25,648 |
| U.S. Government and agencies | 2 | 1 | 6 | 3 |
| Earnings | $8,552 | $8,551 | $25,654 | $25,651 |
| Statements of Changes in Partners' Capital (LP) (USD $) | Total | MERRILL LYNCH PREFERRED FUNDING IV, L.P. | LIMITED PARTNER'S CAPITAL | GENERAL PARTNER'S CAPITAL |
| In Thousands | MERRILL LYNCH PREFERRED FUNDING IV, L.P. | MERRILL LYNCH PREFERRED FUNDING IV, L.P. | ||
| PARTNERS' CAPITAL, Balance, beginning of period at Dec. 31, 2011 | ' | ' | $412,372 | $72,773 |
| Earnings | 22,021 | 25,651 | 22,021 | 3,630 |
| Distributions | ' | ' | -14,680 | -2,422 |
| Distributions payable | ' | ' | -7,341 | -1,209 |
| PARTNERS' CAPITAL, Balance, end of period at Sep. 30, 2012 | ' | 485,144 | 412,372 | 72,772 |
| PARTNERS' CAPITAL, Balance, beginning of period at Jun. 30, 2012 | ' | ' | ' | ' |
| Earnings | 7,341 | 8,551 | ' | ' |
| PARTNERS' CAPITAL, Balance, end of period at Sep. 30, 2012 | ' | 485,144 | ' | ' |
| PARTNERS' CAPITAL, Balance, beginning of period at Dec. 31, 2012 | ' | 485,146 | 412,372 | 72,774 |
| Earnings | 22,021 | 25,654 | 22,021 | 3,633 |
| Distributions | ' | ' | -22,021 | -3,636 |
| Distributions payable | ' | ' | 0 | 0 |
| PARTNERS' CAPITAL, Balance, end of period at Sep. 30, 2013 | ' | 485,143 | 412,372 | 72,771 |
| PARTNERS' CAPITAL, Balance, beginning of period at Jun. 30, 2013 | ' | ' | ' | ' |
| Earnings | 7,341 | 8,552 | ' | ' |
| PARTNERS' CAPITAL, Balance, end of period at Sep. 30, 2013 | ' | $485,143 | ' | ' |
| Statements of Cash Flows (LP) (USD $) | 3 Months Ended | 9 Months Ended | ||
| In Thousands, unless otherwise specified | Sep. 30, 2013 | Sep. 30, 2012 | Sep. 30, 2013 | Sep. 30, 2012 |
| CASH FLOWS FROM OPERATING ACTIVITIES: | ' | ' | ' | ' |
| Earnings | $7,341 | $7,341 | $22,021 | $22,021 |
| Change in interest receivable from affiliates | ' | ' | 0 | -7,341 |
| Cash provided by operating activities | ' | ' | 22,021 | 14,680 |
| CASH FLOWS FROM FINANCING ACTIVITIES: | ' | ' | ' | ' |
| Cash used for financing activities | ' | ' | -22,021 | -14,680 |
| NET CHANGE IN CASH | ' | ' | 0 | 0 |
| CASH, BEGINNING OF PERIOD | ' | ' | 0 | 0 |
| CASH, END OF PERIOD | 0 | 0 | 0 | 0 |
| MERRILL LYNCH PREFERRED FUNDING IV, L.P. | ' | ' | ' | ' |
| CASH FLOWS FROM OPERATING ACTIVITIES: | ' | ' | ' | ' |
| Earnings | 8,552 | 8,551 | 25,654 | 25,651 |
| Accretion of interest on securities issued by U.S. Government and agencies | -2 | -1 | -6 | -3 |
| Change in interest receivable from affiliates | ' | ' | 0 | -8,550 |
| Cash provided by operating activities | ' | ' | 25,648 | 17,098 |
| CASH FLOWS FROM INVESTING ACTIVITIES: | ' | ' | ' | ' |
| Purchases of investment securities | ' | ' | -4,851 | -4,852 |
| Maturities of investment securities | ' | ' | 4,860 | 4,856 |
| Cash provided by investing activities | ' | ' | 9 | 4 |
| CASH FLOWS FROM FINANCING ACTIVITIES: | ' | ' | ' | ' |
| Distributions to limited partner | ' | ' | -22,021 | -14,680 |
| Distributions to general partner | ' | ' | -3,636 | -2,422 |
| Cash used for financing activities | ' | ' | -25,657 | -17,102 |
| NET CHANGE IN CASH | ' | ' | 0 | 0 |
| CASH, BEGINNING OF PERIOD | ' | ' | 0 | 0 |
| CASH, END OF PERIOD | $0 | $0 | $0 | $0 |
| Condensed Statements of Cash Flows (LP) (Parenthetical) (USD $) | Sep. 30, 2012 |
| In Thousands, unless otherwise specified | |
| Distributions payable | $7,341 |
| MERRILL LYNCH PREFERRED FUNDING IV, L.P. | ' |
| Distributions payable | $8,550 |
| Note To Condensed Financial Statements | 9 Months Ended |
| Sep. 30, 2013 | |
| Note To Condensed Financial Statements | ' |
| Merrill Lynch Preferred Capital Trust IV, (the "Trust") is a statutory business trust formed under the Delaware Business Trust Act, as amended. Bank of America Corporation (the “Company” or "Bank of America") is the sole owner of the Trust common securities. Prior to October 1, 2013, Merrill Lynch & Co., Inc. ("ML&Co."), a wholly-owned subsidiary of the Company, was the sole owner of the Trust common securities. On October 1, 2013, the Company merged ML&Co. into the Company pursuant to Section 253 of the General Corporation Law of the State of Delaware, with the Company continuing as the surviving corporation of such merger (the "Merger") and assuming all obligations of ML&Co., including ML&Co.’s obligations under the guarantees and the ML&Co.-issued debentures held by the Partnership (as defined below). | |
| SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES | |
| For a complete discussion of significant accounting policies, refer to the audited financial statements included in the Trust's Annual Report on Form 10-K for the year ended December 31, 2012. | |
| BASIS OF PRESENTATION | |
| These unaudited condensed financial statements should be read in conjunction with the audited financial statements included in the Annual Report on Form 10-K of the Trust for the year ended December 31, 2012. The interim condensed financial statements for the three- and nine-month periods are unaudited; however, all adjustments necessary for a fair presentation of the condensed financial statements have been included. | |
| INVESTMENTS | |
| The Trust's investment in Merrill Lynch Preferred Funding IV, L.P. (the "Partnership") Preferred Securities represents a limited partnership interest in the Partnership and is recorded at cost. Income on the Partnership Preferred Securities is accrued when earned. At September 30, 2013 and December 31, 2012, the estimated fair value of the Partnership Preferred Securities, which are classified as Level 2 in the fair value hierarchy under applicable accounting guidance, was $413 million, which approximated their carrying value. The principal input for the fair value is the exchange traded price of the Preferred Securities issued by the Trust. During the three months ended September 30, 2013, the Company determined that the valuation methodology used in previous reporting periods to estimate the fair value of the Partnership Preferred Securities, for disclosure purposes only, did not fully consider the issuer’s call feature, the inclusion of which resulted in a decrease to the estimated fair value. This revised disclosure had no effect on the Trust’s financial statements or results of operations in the current or prior-year periods. | |
| MERRILL LYNCH PREFERRED FUNDING IV, L.P. | ' |
| Note To Condensed Financial Statements | ' |
| Merrill Lynch Preferred Funding IV, L.P. (the "Partnership") is a limited partnership formed under the Delaware Revised Uniform Limited Partnership Act, as amended. Bank of America Corporation (the “Company” or "Bank of America") is the sole general partner of the Partnership. Prior to October 1, 2013, Merrill Lynch & Co., Inc. (“ML&Co.”), a wholly-owned subsidiary of the Company, was the sole general partner of the Partnership. On October 1, 2013, the Company merged ML&Co. into the Company pursuant to Section 253 of the General Corporation Law of the State of Delaware, with the Company continuing as the surviving corporation of such merger (the "Merger") and assuming all obligations of ML&Co., including ML&Co.’s obligations under the guarantees and the ML&Co.-issued debentures held by the Partnership. | |
| SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES | |
| For a complete discussion of significant accounting policies, refer to the audited financial statements included in the Partnership's Annual Report on Form 10-K for the year ended December 31, 2012. | |
| BASIS OF PRESENTATION | |
| These unaudited condensed financial statements should be read in conjunction with the audited financial statements included in the Annual Report on Form 10-K of the Partnership for the year ended December 31, 2012. The interim condensed financial statements for the three- and nine-month periods are unaudited; however, all adjustments necessary for a fair presentation of the condensed financial statements have been included. | |
| INVESTMENTS | |
| The Partnership’s investment in affiliate debentures is recorded at cost. Its investment in U.S. Government and agency securities is recorded at accreted cost and matures within one year. At September 30, 2013 and December 31, 2012, the estimated fair value of the investment in affiliate debentures, which are classified as Level 2 in the fair value hierarchy under applicable accounting guidance, was $481 million, which approximated their carrying value. The principal input for the fair value is the exchange traded price of the Preferred Securities issued by the Trust. During the three months ended September 30, 2013, the Company determined that the valuation methodology used in previous reporting periods to estimate the fair value of the Partnership Preferred Securities, for disclosure purposes only, did not fully consider the issuer’s call feature, the inclusion of which resulted in a decrease to the estimated fair value. This revised disclosure had no effect on the Trust’s financial statements or results of operations in the current or prior-year periods. At September 30, 2013 and December 31, 2012, the fair value of the investment in U.S. Government and agency securities, which are classified as Level 1 in the fair value hierarchy under applicable accounting guidance, approximated their carrying value. |
| Note To Condensed Financial Statements (Details) (USD $) | Sep. 30, 2013 | Dec. 31, 2012 |
| In Millions, unless otherwise specified | ||
| Investments, Fair Value Disclosure | $413 | $483 |
| MERRILL LYNCH PREFERRED FUNDING IV, L.P. | ' | ' |
| Investments, Fair Value Disclosure | $481 | $563 |
