The asset side of the 2016 balance sheet for BURLINGTON NORTHERN SANTA FE, LLC (BNSF) is below. The company reported total revenues of $19,829 million in 2016 and $21,967 million in 2015.
BURLINGTON NORTHERN SANTA FE, LLC
Consolidated Balance Sheets (excerpts)
(in millions)	Dec. 31, 2016		Dec. 31, 2015
Current assets
Cash and cash equivalents	$3,218		$2,329
Accounts receivable, net of allowances for	1,272		1,198
doubtful accounts of $88 and $74 as of
Dec. 31, 2016 and Dec. 31, 2015,
respectively
Materials and supplies	825		829
Current portion of deferred income taxes	0		245
Other current assets	235		337
Total current assets	5,550		4,938
Property, plant and equipment, net of	61,250		59,510
accumulated depreciation of $6,130 and
$4,845, respectively
Goodwill	14,845		14,845
Intangible assets, net	430		468
Other assets	2,047		1,942
Total assets	$84,122		$81,703
Required:
a.	What proportion of gross accounts receivable does BNSF record as an allowance each year? Interpret the year-over-year change in the ratio.
b.	Calculate the common-size amount for accounts receivable, net, for 2016 and 2015.
c.	Compute the accounts receivable turnover for 2016 and 2015. At December 31, 2014, accounts and other receivables, net were $1,386 million.
d.	Does the accounts receivable turnover you calculated above, seem reasonable for a railway company? Explain.