Goodwill, Customer Relationships and Other Intangible Assets

Goodwill, customer relationships and other intangible assets consisted of the following:



	Successor
	December 31, 2018		December 31, 2017
	(Dollars in millions)
Goodwill	$	11,119	10,837
Customer relationships, less accumulated amortization of $833 and $126	$	7,567	8,845
Other intangible assets subject to amortization:
Trade names, less accumulated amortization of $30 and $4	$	100	126
Developed technology, less accumulated amortization of $67 and $9	310		252
Total other intangible assets, net	$	410	378

The following table shows the rollforward of goodwill from November 1, 2017 through December 31, 2018:



	(Dollars in millions)
As of November 1, 2017	$	10,821
Purchase accounting and other adjustments	16
As of December 31, 2017	10,837
Purchase accounting and other adjustments	340
Effect of foreign currency rate change	(58		)
As of December 31, 2018	$	11,119

Our goodwill balance includes $16 million, of goodwill that was allocated to us from CenturyLink associated with differences in the deferred state income taxes that CenturyLink expects to realize due to its consolidation of our results of operations into its state tax returns.

Total amortization expense for intangible assets for the successor period ended December 31, 2018, the successor period ended December 31, 2017, the predecessor period ended October 31, 2017 and the predecessor year ended December 31, 2016 was $798 million, $139 million, $168 million and $211 million, respectively. As of December 31, 2018, the gross carrying amount of goodwill, customer relationships, indefinite-life and other intangible assets was $20 billion. As of the successor date of December 31, 2018, the weighted average remaining useful lives of our finite-lived intangible assets was 11 years in total; 11 years for customer relationships, 4 years for trade names, and 3 years for developed technology.

We estimate that total amortization expense for intangible assets for the successor years ending 2019 through 2023 will be as follows:



	(Dollars in millions)
2019	$	800
2020	800
2021	800
2022	796
2023	766