Note 6—Drilling Fleet

Construction work in progress—For the nine months ended September 30, 2018 and 2017, the changes in our construction work in progress, including capital expenditures and other capital additions, were as follows (in millions):


	Nine months ended
	September 30,
	2018		2017
Construction work in progress, beginning of period	$	1,392	$	2,171

Capital expenditures
Newbuild construction program		64		299
Other equipment and construction projects		76		87
Total capital expenditures		140		386
Changes in accrued capital additions		(6)		(22)
Construction work in progress acquired in business combination		26		—
Construction work in progress sold		—		(289)

Property and equipment placed into service
Newbuild construction program		(903)		—
Other property and equipment		(61)		(66)
Construction work in progress, end of period	$	588	$	2,180

Impairments of assets held and used—During the three months ended June 30, 2017, we identified indicators that the asset groups in our contract drilling services reporting unit may not be recoverable. Such indicators included recent significant declines in commodity prices and the market value of our stock, a reduction of projected dayrates and a further extension of currently low utilization rates. As a result of our testing, we determined that the carrying amount of the midwater floater asset group was impaired. In the nine months ended September 30, 2017, we recognized a loss of $94 million ($95 million after taxes, or $0.25 per diluted share), associated with the impairment of the midwater floater asset group. We measured the fair value of this asset group by applying a combination of income and market approaches, using projected discounted cash flows and estimates of the exchange price that would be received for the assets in the principal or most advantageous markets for the assets in an orderly transaction between participants as of the measurement date. Our estimate of fair value required us to use significant unobservable inputs, representative of a Level 3 fair value measurement, including assumptions related to the future performance of our contract drilling services reporting unit, such as future commodity prices, projected demand for our services, rig availability and dayrates.

Impairments of assets held for sale—During the nine months ended September 30, 2018, we announced our intent to retire in an environmentally responsible way, the ultra‑deepwater floaters Deepwater Discovery, Deepwater Frontier, Deepwater Millennium and GSF C.R. Luigs and the midwater floaters Songa Delta and Songa Trym, along with related assets. In the three and nine months ended September 30, 2018, we recognized an aggregate loss of $433 million ($0.93 per diluted share) and $981 million ($2.15 per diluted share), respectively, which had no tax effect, associated with the impairment of these assets, which we determined were impaired at the time we classified the assets as held for sale.

During the nine months ended September 30, 2017, we announced our intent to retire in an environmentally responsible way, the ultra-deepwater floaters Cajun Express, Deepwater Pathfinder, GSF Jack Ryan, Sedco Energy and Sedco Express and the deepwater floater Transocean Marianas and the midwater floaters Transocean Prospect and Transocean Searcher, along with related assets. In the three months and nine months ended September 30, 2017, we recognized an aggregate loss of $1.4 billion ($3.54 per diluted share) and $1.4 billion ($3.60 per diluted share), respectively, which had no tax effect, associated with the impairment of these assets, which we determined were impaired at the time we classified the assets as held for sale.

We measured the impairment of the drilling units and related equipment as the amount by which the carrying amount exceeded the estimated fair value less costs to sell. We estimated the fair value of the assets using significant other observable inputs, representative of a Level 2 fair value measurement, including indicative market values for the drilling units and related assets to be sold for scrap value.

Dispositions—During the nine months ended September 30, 2018, in connection with our efforts to dispose of non‑strategic assets, we completed the sale of the ultra‑deepwater floaters Cajun Express, Deepwater Discovery, Deepwater Pathfinder, Sedco Energy and Sedco Express, the deepwater floater Transocean Marianas and the midwater floater Songa Trym, along with related assets. In the nine months ended September 30, 2018, we received aggregate net cash proceeds of $31 million and recognized an aggregate net gain of $6 million ($0.02 per diluted share), which had no tax effect, associated with the disposal of these assets. In the nine months ended September 30, 2018, we received aggregate net cash proceeds of $6 million and recognized an aggregate net loss of $6 million associated with the disposal of assets unrelated to rig sales.

On May 31, 2017, we completed the sale of 10 high‑specification jackups, including GSF Constellation I, GSF Constellation II, GSF Galaxy I, GSF Galaxy II, GSF Galaxy III, GSF Monarch, Transocean Andaman, Transocean Ao Thai, Transocean Honor and Transocean Siam Driller, along with related assets, and novated the contracts relating to the construction of five high‑specification jackups, together with related assets. In the nine months ended September 30, 2017, we received aggregate net cash proceeds of $319 million and recognized an aggregate net loss of $1.6 billion ($4.08 per diluted share), which had no tax effect, associated with the disposal of these assets. Following the completion of the sale, we agreed to continue to operate three of these high‑specification jackups through completion or novation of the drilling contracts, one of which we continue to operate as of September 30, 2018. In the three and nine months ended September 30, 2018, our operating results included income of $10 million and $42 million, respectively, before taxes, associated with the high specification jackups that we continued to operate during the period. In the three and nine months ended September 30, 2017, excluding our loss on the disposal of these assets, our operating results included income of $19 million and $46 million, respectively, before taxes, associated with the high‑specification jackup asset group.

During the nine months ended September 30, 2017, we also completed the sale of the midwater floater GSF Rig 140, along with related assets. In the nine months ended September 30, 2017, we received aggregate net cash proceeds of $3 million and recognized an aggregate net gain of $2 million associated with the disposal of this asset. In the three and nine months ended September 30, 2017, we received aggregate net cash proceeds of $1 million and $8 million, respectively, and recognized an aggregate net loss of $9 million and $8 million, respectively, associated with the disposal of assets unrelated to rig sales.

Assets held for sale—At September 30, 2018, the aggregate carrying amount of our assets held for sale, including the ultra‑deepwater floaters Deepwater Frontier, Deepwater Millennium and GSF C.R. Luigs and the midwater floater Songa Delta, along with related assets, was $26 million, recorded in other current assets. At December 31, 2017, the aggregate carrying amount of our assets held for sale, including the ultra‑deepwater floaters Cajun Express, Deepwater Pathfinder, Sedco Energy and Sedco Express and the deepwater floater Transocean Marianas, along with related assets, was $22 million, recorded in other current assets.