6. Intangible Assets

The changes in the carrying amount of goodwill and other intangible assets of the Company between January 1, 2013 and June 30, 2013 are as follows:


(in $ millions)	January 1, 2013		Additions		Retirements		Foreign Exchange		June 30, 2013
Non-Amortizable Assets:
Goodwill		986		—		—		—		986
Trademarks and tradenames		314		—		—		—		314
Other Intangible Assets:
Acquired customer relationships		1,129		—		—		—		1,129
Accumulated amortization		(530)		(40)		—		—		(570)

Acquired customer relationships, net		599		(40)		—		—		559

Customer loyalty payments		274		36		(50)		(3)		257
Accumulated amortization		(156)		(29)		50		—		(135)

Customer loyalty payments, net		118		7		—		(3)		122

Other intangible assets, net		717		(33)		—		(3)		681

The changes in the carrying amount of goodwill and other intangible assets of the Company between January 1, 2012 and June 30, 2012 are as follows:


(in $ millions)	January 1, 2012		Additions		Retirements		Foreign Exchange		June 30, 2012
Non-Amortizable Assets:
Goodwill		986		—		—		—		986
Trademarks and tradenames		314		—		—		—		314
Other Intangible Assets:
Acquired customer relationships		1,129		—		—		—		1,129
Accumulated amortization		(448)		(41)		—		—		(489)

Acquired customer relationships, net		681		(41)		—		—		640

Customer loyalty payments		269		27		(19)		—		277
Accumulated amortization		(140)		(31)		19		—		(152)

Customer loyalty payments, net		129		(4)		—		—		125

Other intangible assets, net		810		(45)		—		—		765

Customer loyalty payments are made with an objective of increasing the number of travel bookings and/or to improve the travel agents’ and/or travel providers’ loyalty and which are instrumented through agreements with a term over a year. Under the contractual terms, the travel agent commits to achieve certain economic objectives for the Company. Such costs are specifically identifiable to individual contracts with travel agents and/or travel providers, which have determinable contractual lives. Due to the contractual nature of the payments, the Company believes that such assets are more appropriately classified as internally developed identifiable intangible assets and, as a result, the Company has presented them within intangible assets with conforming changes to prior periods. As of December 31 2012, the Company included $50 million and $68 million as “Development advances” within other current assets and other non-current assets, respectively, which have been re-classed as other intangible assets to conform to current period presentation.

Amortization expense for acquired customer relationships was $40 million and $41 million for the six months ended June 30, 2013 and 2012, respectively, and is included as a component of depreciation and amortization in the Company’s consolidated condensed statements of operations.

Amortization expense for customer loyalty payments was $29 million and $31 million for the six months ended June 30, 2013 and 2012, respectively, and is included as components of revenue and cost of revenue in the Company’s consolidated condensed statements of operations.

The Company expects amortization expense relating to acquired customer relationships and customer loyalty payments to be:


	Twelve Months Ending June 30,
(in $ millions)	Acquired Customer Relationships		Customer Loyalty Payments
2014		77		56
2015		72		37
2016		58		17
2017		46		8
2018		41		2