In the normal course of business, our operations are exposed to market risks, including the effect of changes in foreign currency exchange rates and interest rates. We may enter into derivative financial instruments to offset these underlying market risks. There have been no significant changes in our policy or strategy from what was disclosed in our Annual Report on Form 10-K for the year ended December 31, 2018.

The following table presents the fair value of our derivative financial instruments recognized within Other Assets and Other Liabilities on the Consolidated Balance Sheets (in thousands):

	March 31, 2019				December 31, 2018
	Asset		Liability		Asset		Liability
Undesignated derivatives
Foreign currency contracts
Forwards
Brazilian real	$	-	$	-	$	80	$	-
British pound sterling		717		734		2,266		324
Canadian dollar		2,080		-		3,336		53
Euro		13,605		374		7,895		1,922
Japanese yen		3,666		76		3,334		1,318
Mexican peso		-		-		159		-

Interest rate swaps
U.S. dollar		-		39		27		-

Designated derivatives
Foreign currency contracts
Net investment hedges
Brazilian real		-		-		-		3,165
British pound sterling		460		3,526		-		949
Canadian dollar		3,893		-		5,634		-

Interest rate swaps
Cash flow hedges
Euro		-		368		-		428
Total fair value of derivatives	$	24,421	$	5,117	$	22,731	$	8,159

The following table summarizes the activity of our undesignated foreign currency contracts for the three months ended March 31 (in millions, except for weighted average forward rates and number of active contracts):

	2019															2018
	BRL			CAD			EUR			GBP			JPY			CAD			CNY			EUR			GBP			JPY
Notional amounts at January 1	$	5		$	55		$	314		$	118		$	177		$	56		$	-		$	233		$	132		$	153
New contracts		489			-			-			112			-			5			80			28			-			-
Matured, expired or settled contracts		(494	)		(9	)		(35	)		(21	)		(20	)		(6	)		(80	)		(25	)		(24	)		(19	)
Notional amounts at March 31	$	-		$	46		$	279		$	209		$	157		$	55		$	-		$	236		$	108		$	134

Weighted average forward rate at March 31		-			1.28			1.21			1.22			104.86			1.28			-			1.18			1.30			106.20
Active contracts at March 31		-			20			29			22			30			24			-			29			18			30

The following table summarizes the undesignated derivative financial instruments exercised and associated realized gains (losses) and unrealized gains (losses) in Foreign Currency and Derivative Gains (Losses), Net in the Consolidated Statements of Income (in millions, except for number of exercised contracts):

The following table summarizes the activity of our foreign currency contracts designated as net investment hedges for the three months ended March 31 (in millions, except for weighted average forward rates and number of active contracts):

	2019							2018
	BRL			CAD		GBP		CAD
Notional amounts at January 1	$	460		$	100	$	127	$	99
New contracts		489			-		262		100
Matured, expired or settled contracts		(949	)		-		-		(99	)
Notional amounts at March 31	$	-		$	100	$	389	$	100

Weighted average forward rate at March 31		-			1.28		1.30		1.28
Active contracts at March 31		-			2		6		2

The following table summarizes the activity of our interest rate swaps designated as cash flow hedges for the three months ended March 31 (in millions):

The following table summarizes our debt and accrued interest, designated as a hedge of our net investment in international subsidiaries (in millions):

The following table summarizes the recognized unrealized losses in Foreign Currency and Derivative Gains (Losses), Net on the remeasurement of the unhedged portion of our debt and accrued interest for the three months ended March 31 (in millions):

The unrealized loss on the unhedged portion recognized during the three months ended March 31, 2019 was not material.

The change in Other Comprehensive Income (Loss) in the Consolidated Statements of Comprehensive Income during the periods presented is due to the translation into U.S. dollars on consolidation of the financial statements of our consolidated subsidiaries whose functional currency is not the U.S. dollar. The change in fair value of the effective portion of our derivative financial instruments that have been designated as net investment hedges and cash flow hedges and the translation of our nonderivative financial instruments as discussed above are also included in Other Comprehensive Income (Loss).

The following table presents these changes in Other Comprehensive Income (Loss) (in thousands):

	Three Months Ended March 31,
	2019			2018
Derivative net investment hedges	$	(19,452	)	$	3,093
Nonderivative net investment hedges		63,657			(109,877	)
Cumulative translation adjustment		15,875			111,554
Total foreign currency translation gains, net	$	60,080		$	4,770

Cash flow hedges (1)	$	1,105		$	(9,285	)
Our share of derivatives from unconsolidated co-investment ventures		(3,738	)		2,998
Total unrealized losses on derivative contracts, net	$	(2,633	)	$	(6,287	)
Total change in other comprehensive income (loss)	$	57,447		$	(1,517	)

(1)	We estimate an additional expense of $4.2 million will be reclassified to Interest Expense over the next 12 months from March 31, 2019, due to the amortization of previously settled derivatives designated as cash flow hedges.

There have been no significant changes in our policy from what was disclosed in our Annual Report on Form 10-K for the year ended December 31, 2018.

At March 31, 2019 and December 31, 2018, other than the derivatives discussed previously, we did not have any significant financial assets or financial liabilities that were measured at fair value on a recurring basis in the Consolidated Financial Statements. All of our derivatives held at March 31, 2019 and December 31, 2018, were classified as Level 2 of the fair value hierarchy.

Acquired properties and assets we expect to sell or contribute met the criteria to be measured on a nonrecurring basis at fair value and the lower of their carrying amount or their estimated fair value less the costs to sell, respectively, at March 31, 2019 and December 31, 2018. At March 31, 2019 and December 31, 2018, we estimate the fair value of our properties using Level 2 or Level 3 inputs from the fair value hierarchy. See more information on our acquired properties and assets held for sale or contribution in Notes 2, 3 and 5, respectively.

At March 31, 2019 and December 31, 2018, the carrying amounts of certain financial instruments, including cash and cash equivalents, accounts and notes receivable, accounts payable and accrued expenses were representative of their fair values.

The differences in the fair value of our debt from the carrying value in the table below were the result of differences in interest rates or borrowing spreads that were available to us at March 31, 2019 and December 31, 2018, as compared with those in effect when the debt was issued or assumed, including reduced borrowing spreads due to our improved credit ratings. The senior notes and many of the issuances of secured mortgage debt contain pre-payment penalties or yield maintenance provisions that could make the cost of refinancing the debt at lower rates exceed the benefit that would be derived from doing so.

The following table reflects the carrying amounts and estimated fair values of our debt (in thousands):

	March 31, 2019				December 31, 2018
	Carrying Value		Fair Value		Carrying Value		Fair Value
Credit Facilities	$	26,180	$	26,180	$	50,500	$	50,513
Senior notes		8,314,678		8,846,176		8,304,147		8,606,864
Term loans and unsecured other		1,411,343		1,433,838		1,921,428		1,946,335
Secured mortgage		953,938		992,924		813,740		849,417
Total	$	10,706,139	$	11,299,118	$	11,089,815	$	11,453,129