<Page>
EXHIBIT 4
TRANSCANADA PIPELINES LIMITED
U.S. GAAP CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)
CONDENSED STATEMENT OF CONSOLIDATED INCOME AND COMPREHENSIVE INCOME IN
ACCORDANCE WITH U.S. GAAP(1)
<Table>
<Caption>
Three months ended
March 31
---------------------------
(MILLIONS OF DOLLARS) 2004 2003
- ------------------------------------------------------------------------- --------- -----------
Revenues(2) 1,143 1,177
--------- -----------
Cost of sales(2) 104 151
Other costs and expenses 387 422
Depreciation 212 185
--------- -----------
703 758
--------- -----------
Operating income 440 419
Other (income)/expenses
Equity income(1)(3)(4) (109) (119)
Other expenses(4)(5)(6) 204 214
Income taxes 126 123
--------- -----------
221 218
--------- -----------
Income before cumulative effect of the application of
accounting changes in accordance with U.S. GAAP 219 201
Cumulative effect of the application of accounting changes, net
of tax(2) - (13)
--------- -----------
NET INCOME IN ACCORDANCE WITH U.S. GAAP 219 188
Adjustments affecting comprehensive income under U.S. GAAP
Foreign currency translation adjustment, net of tax(7) 3 (15)
Changes in minimum pension liability, net of tax(8) 25 3
Unrealized (loss)/gain on derivatives, net of tax(4) (13) 8
--------- -----------
COMPREHENSIVE INCOME IN ACCORDANCE WITH U.S. GAAP 234 184
--------- -----------
--------- -----------
</Table>
RECONCILIATION OF INCOME FROM CONTINUING OPERATIONS
<Table>
<Caption>
Three months ended
March 31
---------------------
(MILLIONS OF DOLLARS) 2004 2003
- ------------------------------------------------------------------------- ---- ----
Net income from continuing operations in accordance with
Canadian GAAP 228 223
U.S. GAAP adjustments
Preferred securities charges(5) (12) (14)
Tax impact of preferred securities charges 4 5
Unrealized loss on foreign exchange and interest rate
derivatives(4) (4) (6)
Tax impact of loss on foreign exchange and interest rate
derivatives 1 2
Unrealized gain/(loss) on energy trading contracts(2) 4 (11)
Tax impact of unrealized gain/(loss) on energy trading contracts (1) 4
Equity loss(3) (1) (3)
Tax impact of equity loss - 1
---- ----
Income from continuing operations in accordance with U.S. GAAP 219 201
---- ----
---- ----
</Table>
Page 1 of 5
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CONDENSED BALANCE SHEET IN ACCORDANCE WITH U.S. GAAP(1)
<Table>
<Caption>
March 31, December 31,
(MILLIONS OF DOLLARS) 2004 2003
- ---------------------------------------------------------------- ----------------- ----------------
Current assets 1,031 1,017
Long-term investments(3)(9) 1,826 1,760
Plant, property and equipment 15,665 15,798
Regulatory asset(10) 2,632 2,721
Other assets(4) 1,379 1,192
----------------- ----------------
22,533 22,488
----------------- ----------------
----------------- ----------------
Current liabilities(11) 1,770 2,117
Deferred amounts(2)(4)(9) 794 741
Long-term debt(4) 9,908 9,494
Deferred income taxes(10) 2,963 3,039
Preferred securities(12) 603 694
Non-controlling interests 85 82
Shareholders' equity 6,410 6,321
----------------- ----------------
22,533 22,488
----------------- ----------------
----------------- ----------------
</Table>
STATEMENT OF OTHER COMPREHENSIVE INCOME IN ACCORDANCE WITH U.S. GAAP
<Table>
<Caption>
Cumulative Minimum Cash Flow
Translation Pension Liability Hedges
(MILLIONS OF DOLLARS) Account (SFAS No. 87) (SFAS No. 133) Total
- ---------------------------------------------------------- --------------- ------------------ ---------------- ---------
Balance at January 1, 2004 (40) (98) (5) (143)
Changes in minimum pension liability, net of tax
of $(13)(8) - 25 - 25
Unrealized loss on derivatives, net of tax of $7(4) - - (13) (13)
Foreign currency translation adjustment, net of tax
of $6(7) 3 - - 3
--------------- ------------------ ---------------- ---------
BALANCE AT MARCH 31, 2004 (37) (73) (18) (128)
--------------- ------------------ ---------------- ---------
--------------- ------------------ ---------------- ---------
Balance at January 1, 2003 14 (96) (13) (95)
Changes in minimum pension liability, net of tax
of $(1)(8) - 3 - 3
Unrealized gain on derivatives, net of tax of nil(4) - - 8 8
Foreign currency translation adjustment, net of tax
of $(21)(7) (15) - - (15)
--------------- ------------------ ---------------- ---------
Balance at March 31, 2003 (1) (93) (5) (99)
--------------- ------------------ ---------------- ---------
--------------- ------------------ ---------------- ---------
</Table>
(1) In accordance with U.S. GAAP, the Condensed Statement of Consolidated
Income and Balance Sheet are prepared using the equity method of accounting
for joint ventures. Excluding the impact of other U.S. GAAP adjustments,
the use of the proportionate consolidation method of accounting for joint
ventures, as required under Canadian GAAP, results in the same net income
and Shareholders' Equity.
Page 2 of 5
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(2) Substantially all of the energy trading contracts are now accounted for as
hedges under U.S. and Canadian GAAP. The energy trading contracts that
qualified as hedges were accounted for as hedges under the provisions of
Statement of Financial Accounting Standards (SFAS) No. 133. All gains or
losses on the contracts that did not qualify as hedges, and the amounts of
any ineffectiveness on the hedging contracts, are included in income each
period. Substantially all of the amounts recorded in 2004 and 2003 as
differences between U.S. and Canadian GAAP relate to gains and losses on
contracts for periods before they were documented as hedges for purposes of
U.S. GAAP.
(3) Under Canadian GAAP, pre-operating costs incurred during the commissioning
phase of a new project are deferred until commercial production levels are
achieved. After such time, those costs are amortized over the estimated
life of the project. Under U.S. GAAP, such costs are expensed as incurred.
Certain start-up costs incurred by Bruce Power L.P. (an equity investment)
are required to be expensed under U.S. GAAP.
(4) Effective January 1, 2004, all foreign exchange and interest rate
derivatives are recorded in the Company's Consolidated Financial Statements
at fair value under Canadian GAAP. Under the provisions of SFAS No. 133
"Accounting for Derivatives and Hedging Activities", all derivatives are
recognized as assets and liabilities on the balance sheet and measured at
fair value. For derivatives designated as fair value hedges, changes in the
fair value are recognized in earnings together with an equal or lesser
amount of changes in the fair value of the hedged item attributable to the
hedged risk. For derivatives designated as cash flow hedges, changes in the
fair value of the derivatives that are effective in offsetting the hedged
risk are recognized in other comprehensive income until the hedged item is
recognized in earnings. Any ineffective portion of the change in fair value
is recognized in earnings each period. Substantially all of the amounts
recorded in 2004 as differences between U.S. and Canadian GAAP, for income
from continuing operations, relate to the differences in accounting
treatment with respect to the hedged items and, for comprehensive income,
relate to cash flow hedges.
(5) Under U.S. GAAP, the financial charges related to preferred securities are
recognized as an expense, rather than dividends.
(6) Other expenses included an allowance for funds used during construction of
$1 million for the three months ended March 31, 2004 (March 31, 2003 - $1
million).
(7) Under U.S. GAAP, changes in the foreign currency translation adjustment
account must be recorded as a component of comprehensive income.
(8) Under U.S. GAAP, a net loss recognized pursuant to SFAS No. 87 "Employers'
Accounting for Pensions" as an additional pension liability not yet
recognized as net period pension cost, must be recorded as a component of
comprehensive income. The components of net benefit cost recognized for the
Company's defined benefit pension plans and other post-employment benefit
plans for the three months ended March 31 are as follows.
<Table>
<Caption>
PENSION BENEFIT OTHER BENEFIT
PLANS PLANS
------------------- -------------------
(MILLIONS OF DOLLARS) 2004 2003 2004 2003
---------------------------------------------------------- ------- -------- -------- --------
Current service cost 7 6 - -
Interest cost 14 13 1 1
Expected return on plan assets (14) (13) - -
Amortization of transitional obligation related to
regulated business - - 1 1
Amortization of net actuarial loss 3 2 1 1
Amortization of past service cost 1 1 - -
------- -------- -------- --------
Net benefit cost recognized 11 9 3 3
------- -------- -------- --------
------- -------- -------- --------
</Table>
Page 3 of 5
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(9) Effective January 1, 2003, the Company adopted the provisions of Financial
Interpretation (FIN) 45 that require the recognition of a liability for the
fair value of certain guarantees that require payments contingent on
specified types of future events. The measurement standards of FIN 45 are
applicable to guarantees entered into after January 1, 2003. For U.S. GAAP
purposes, the fair value of guarantees recorded as a liability at March 31,
2004 was $10 million (December 31, 2003 - $4 million) and relates to the
Company's equity interest in Bruce Power L.P.
(10) Under U.S. GAAP, the Company is required to record a deferred income tax
liability for its cost-of-service regulated businesses. As these deferred
income taxes are recoverable through future revenues, a corresponding
regulatory asset is recorded for U.S. GAAP purposes.
(11) Current liabilities at March 31, 2004 include dividends payable of $146
million (December 31, 2003 - $136 million) and current taxes payable of
$217 million (December 31, 2003 - $271 million).
(12) Under U.S. GAAP, the preferred securities are classified as a liability.
The fair value of the preferred securities at March 31, 2004 was $624
million (December 31, 2003 - $612 million). The Company made preferred
securities charges payments of $12 million for the three months ended March
31, 2004 (March 31, 2003 - $14 million).
(13) The Company's Statement of Consolidated Cash Flows under U.S. GAAP would be
identical to that under Canadian GAAP except that the preferred securities
charges would be classified with funds generated from continuing
operations.
(14) Effective December 31, 2003, the Company adopted the provisions of FIN 46
(Revised) "Consolidation of Variable Interest Entities" that requires the
consolidation of certain entities that are controlled through financial
interests that indicate control (referred to as `variable interests').
Adopting these provisions has had no impact on the U.S. GAAP financial
statements of the Company.
Page 4 of 5
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SUMMARIZED FINANCIAL INFORMATION OF LONG-TERM INVESTMENTS(15)
<Table>
<Caption>
Three months ended
March 31
-----------------------------
(MILLIONS OF DOLLARS) 2004 2003
- -------------------------------------------------------------------------------- ------------ -----------
INCOME
Revenues 275 280
Other costs and expenses (119) (105)
Depreciation (33) (38)
Financial charges and other (15) (25)
------------ -----------
Proportionate share of income before income taxes of long-term
investments 108 112
------------ -----------
------------ -----------
</Table>
<Table>
<Caption>
March 31, December 31,
(MILLIONS OF DOLLARS) 2004 2003
- ----------------------------------------------------------------- ------------------ -----------------
BALANCE SHEET
Current assets 317 385
Plant, property and equipment 3,048 2,944
Current liabilities (185) (204)
Deferred amounts (net) (291) (286)
Non-recourse debt (1,052) (1,060)
Deferred income taxes (17) (19)
------------------ -----------------
Proportionate share of net assets of long-term investments 1,820 1,760
------------------ -----------------
------------------ -----------------
</Table>
(15) This includes those investments that are accounted for by the equity method
under U.S. GAAP (including those that are accounted for by the
proportionate consolidation method under Canadian GAAP).
Page 5 of 5