Use the following balance sheets and income statement to answer this question

Ensco Corp ($ Million)	2019	2020			2019	2020
Cash and equivalents	364,246	96,095		Account payable	103,852	159,420
Account receivables	460,540	620,489		Accrued liabilities	192,898	176,615
Inventories	74,262	96,332		Deferred revenues	115,000	40,000
Prepaid expense	57,265	82,312		Notes payables	4,979	5,129
Total current assets	956,313	895,228		Total current liabilities	416,729	381,164
Long-term securities investments	347,924	451,144		Long-term debt	235,000	195,000
Net property plant	3,677,070	4,351,571		Other long-term financing	1,082,115	1,309,923
Other long-term operating assets	22,584	23,142		Common stock	10,724	10,760
Total assets	5,003,891	5,721,085		Paid in capital	210,909	236,240
				Retained earnings	2,954,210	3,505,295
				Other equity investment	98,908	166,807
Ensco Corp ($ Million)	2019	2020		Treasury stock	-4,704	-84,104
Total net sales	2,543,894	3,151,802		Total equity	3,270,047	3,834,998
Operating cost	1,432,602	1,750,510		Total liabilities and equity	5,003,891	5,721,085
Depreciation expense	315,468	387,549
Research and development expense	15,764	16,060
General admin expense	77,549	88,084
Operating income	702,511	909,599
Interest income	1,911	1,634
Interest expense	-17,355	-8,653
Income before income tax	687,067	902,580
Income tax provision	252,399	328,971
Net income	434,668	573,609
Dividend payments	21,402	22,524

Calculate the firms free-cash-flow (FCF) during 2020 and carefully explain the meaning of the free cash flow you have calculated to the firm's investors.