14. SUPPLEMENTAL FINANCIAL INFORMATION

Consolidated Balance Sheet Information

Accounts receivable, net, as of December 31, 2017 and 2016 consisted of the following (in millions):



	2017			2016
Trade	$	335.4		$	358.4
Other	33.6			24.5
	369.0			382.9
Allowance for doubtful accounts	(23.6		)	(21.9		)
	$	345.4		$	361.0

Other current assets as of December 31, 2017 and 2016 consisted of the following (in millions):



	2017		2016
Inventory	$	278.8	$	225.2
Prepaid taxes	43.5		30.7
Deferred costs	29.7		32.4
Prepaid expenses	14.2		7.9
Other	15.0		19.8
	$	381.2	$	316.0

Other assets, net, as of December 31, 2017 and 2016 consisted of the following (in millions):



	2017		2016
Deferred tax assets	$	38.8	$	69.3
Deferred costs	37.4		35.7
Supplemental executive retirement plan assets	30.9		27.7
Intangible assets	15.7		0.3
Prepaid taxes on intercompany transfers of property	—		33.0
Other	17.4		9.9
	$	140.2	$	175.9

Accrued liabilities and other as of December 31, 2017 and 2016 consisted of the following (in millions):



	2017		2016
Personnel costs	$	112.0	$	124.0
Accrued interest	83.1		71.7
Deferred revenue	73.0		116.7
Taxes	46.4		40.7
Derivative liabilities	.4		12.7
Other	11.0		10.8
	$	325.9	$	376.6

Other liabilities as of December 31, 2017 and 2016 consisted of the following (in millions):



	2017		2016
Unrecognized tax benefits (inclusive of interest and penalties)	$	178.0	$	142.9
Intangible liabilities	59.6		—
Deferred revenue	51.2		120.9
Supplemental executive retirement plan liabilities	32.0		28.9
Deferred tax liabilities	18.5		5.2
Personnel costs	18.1		13.5
Deferred rent	17.1		9.4
Other	12.2		1.7
	$	386.7	$	322.5

Accumulated other comprehensive income as of December 31, 2017 and 2016 consisted of the following (in millions):



	2017			2016
Derivative instruments	$	22.5		$	13.6
Currency translation adjustment	7.8			7.6
Other	(1.7		)	(2.2		)
	$	28.6		$	19.0

Consolidated Statement of Operations Information

Repair and maintenance expense related to continuing operations for each of the years in the three-year period ended December 31, 2017 was as follows (in millions):



	2017		2016		2015
Repair and maintenance expense	$	188.7	$	151.1	$	270.1

Consolidated Statement of Cash Flows Information

Net cash provided by operating activities of continuing operations attributable to the net change in operating assets and liabilities for each of the years in the three-year period ended December 31, 2017 was as follows (in millions):



	2017			2016			2015
Decrease in accounts receivable	$	83.2		$	222.4		$	246.1
(Increase) decrease in other assets	(14.0		)	44.0			25.7
Decrease in liabilities	(3.8		)	(125.8		)	(158.3		)
	$	65.4		$	140.6		$	113.5

During 2017, the net change in operating assets and liabilities declined by $75.2 million as compared to the prior year. The net change during 2017 was primarily due to a decline in accounts receivable due to lower revenues from contract drilling services, partially offset by an increase in prepaid taxes primarily due to the U.S. tax reform and a decline in liabilities related to lower operating levels across the fleet.

During 2016, the net change in operating assets and liabilities increased by $27.1 million as compared to the prior year. The net change during 2016 was primarily due to a decline in accounts receivable related to lower revenues from contract drilling services and a decline in prepaid taxes and other assets due to collections during the year, partially offset by a decline in liabilities related to lower operating levels across the fleet.

Cash paid for interest and income taxes for each of the years in the three-year period ended December 31, 2017 was as follows (in millions):



	2017		2016		2015
Interest, net of amounts capitalized	$	199.8	$	264.8	$	249.3
Income taxes	62.8		56.4		97.3

Capitalized interest totaled $72.5 million, $45.7 million and $87.4 million during the years ended December 31, 2017, 2016 and 2015, respectively. Capital expenditure accruals totaling $234.3 million, $11.5 million and $60.9 million for the years ended December 31, 2017, 2016 and 2015, respectively, were excluded from investing activities in our consolidated statements of cash flows. In January 2018, we paid $207.4 million of the $218.3 million unpaid balance for ENSCO 123. The $207.4 million milestone payment was invoiced and included in accounts payable - trade as of December 31, 2017 on our consolidated balance sheet.

Amortization, net, includes amortization of deferred mobilization revenues and costs, deferred capital upgrade revenues, intangible amortization and other amortization.

Other includes amortization of debt discounts and premiums, deferred financing costs, deferred charges for income taxes incurred on intercompany transfers of drilling rigs and other items.

Concentration of Risk

We are exposed to credit risk relating to our receivables from customers, our cash and cash equivalents and investments and our use of derivatives in connection with the management of foreign currency exchange rate risk. We mitigate our credit risk relating to receivables from customers, which consist primarily of major international, government-owned and independent oil and gas companies, by performing ongoing credit evaluations. We also maintain reserves for potential credit losses, which generally have been within our expectations. We mitigate our credit risk relating to cash and investments by focusing on diversification and quality of instruments. Cash equivalents and short-term investments consist of a portfolio of high-grade instruments. Custody of cash and cash equivalents and short-term investments is maintained at several well-capitalized financial institutions, and we monitor the financial condition of those financial institutions.

We mitigate our credit risk relating to counterparties of our derivatives through a variety of techniques, including transacting with multiple, high-quality financial institutions, thereby limiting our exposure to individual counterparties and by entering into ISDA Master Agreements, which include provisions for a legally enforceable master netting agreement, with our derivative counterparties. See "Note 6 - Derivative Instruments" for additional information on our derivative activity.

The terms of the ISDA agreements may also include credit support requirements, cross default provisions, termination events or set-off provisions. Legally enforceable master netting agreements reduce credit risk by providing protection in bankruptcy in certain circumstances and generally permitting the closeout and netting of transactions with the same counterparty upon the occurrence of certain events.

Consolidated revenues by customer for the years ended December 31, 2017, 2016 and 2015 were as follows:



	2017		2016		2015
Total⁽¹⁾	22	%	13	%	9	%
BP ⁽²⁾	15	%	12	%	18	%
Petrobras⁽³⁾	11	%	9	%	14	%
Other	52	%	66	%	59	%
	100	%	100	%	100	%


⁽¹⁾	For the years ended December 31, 2017, 2016 and 2015, all Total revenues were attributable to the Floater segment.


⁽²⁾	For the years ended December 31, 2017 and 2015, 78% and 81%, respectively, of the revenues provided by BP were attributable to our Floaters segment and the remaining revenues were attributable to our Other segment. For the year ended December 31, 2016, 76%, 17% and 7% of the revenues provided by BP were attributable to our Floaters, Other and Jackups segments, respectively.

For the year ended December 31, 2015, excluding the impact of ENSCO DS-4 lump-sum termination payments of $110.6 million, revenues from BP represented 15% of total revenue.


⁽³⁾	For the years ended December 31, 2017, 2016 and 2015, all Petrobras revenues were attributable to our Floaters segment.

For purposes of our geographic disclosure, we attribute revenues to the geographic location where such revenues are earned. Consolidated revenues by region, including the United Kingdom, our country of domicile, for the years ended December 31, 2017, 2016 and 2015 were as follows (in millions):



	2017		2016		2015
Angola⁽¹⁾	$	445.7	$	552.1	$	586.5
Egypt⁽²⁾	214.8		141.2		—
Australia⁽³⁾	206.7		222.8		223.2
Brazil⁽²⁾	196.2		298.0		468.5
Saudi Arabia⁽⁴⁾	171.8		210.6		255.2
United Kingdom⁽⁴⁾	164.6		246.2		400.7
U.S. Gulf of Mexico⁽⁵⁾	149.8		531.7		1,151.5
Other	293.4		573.8		977.8
	$	1,843.0	$	2,776.4	$	4,063.4


⁽¹⁾	For the years ended December 31, 2017, 2016 and 2015, 88%, 87% and 88% of the revenues earned in Angola, respectively, were attributable to our Floaters segment with the remaining revenues attributable to our Jackups segment.


⁽²⁾	For the years ended December 31, 2017, 2016 and 2015, all revenues were attributable to our Floaters segment.


⁽³⁾	For the years ended December 31, 2017, 2016 and 2015, 87%, 95% and 100% of the revenues earned in Australia, respectively, were attributable to our Floaters segment with the remaining revenues attributable to our Jackups segment.


⁽⁴⁾	For the years ended December 31, 2017, 2016 and 2015, all revenues were attributable to our Jackups segment.


⁽⁵⁾	For the years ended December 31, 2017, 2016 and 2015, 29%, 82% and 86% of the revenues earned in the U.S. Gulf of Mexico, respectively, were attributable to our Floaters segment. For the years ended December 31, 2017, 2016 and 2015, 31%, 7% and 9% of revenues were attributable to our Jackups segment.