Intangibles	3 Months Ended
Mar. 31, 2013
Intangibles
Intangibles	(8) Intangibles At March 31, 2013 and December 31, 2012, intangible lease assets, comprised of lease-up intangibles, above market tenant lease intangibles and below market ground lease intangibles, were $797 million and $794 million, respectively. At March 31, 2013 and December 31, 2012, the accumulated amortization of intangible assets was $259 million and $241 million, respectively. At both March 31, 2013 and December 31, 2012, intangible lease liabilities, comprised of below market lease intangibles and above market ground lease intangible liabilities were $199 million. At March 31, 2013 and December 31, 2012, the accumulated amortization of intangible liabilities was $97 million and $93 million, respectively.

(8) Intangibles

At March 31, 2013 and December 31, 2012, intangible lease assets, comprised of lease-up intangibles, above market tenant lease intangibles and below market ground lease intangibles, were $797 million and $794 million, respectively. At March 31, 2013 and December 31, 2012, the accumulated amortization of intangible assets was $259 million and $241 million, respectively.

At both March 31, 2013 and December 31, 2012, intangible lease liabilities, comprised of below market lease intangibles and above market ground lease intangible liabilities were $199 million. At March 31, 2013 and December 31, 2012, the accumulated amortization of intangible liabilities was $97 million and $93 million, respectively.