XML 93 R38.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Revenue Reserves (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2016
Reserves for Discounts and Allowances [Abstract] |
Analysis of the change in reserves |
(In millions) | Discounts |  | Contractual Adjustments |  | Returns |  | Total
2016 |  |  |  |  |  |  |
Beginning balance | $ | 56.1 |  |  | $ | 548.7 |  |  | $ | 57.9 |  |  | $ | 662.7 |
Current provisions relating to sales in current year | 592.6 |  |  | 2,044.5 |  |  | 30.9 |  |  | 2,668.0 |
Adjustments relating to prior years | (1.4 | ) |  | 1.5 |  |  | (16.8 | ) |  | (16.7 | )
Payments/returns relating to sales in current year | (522.5 | ) |  | (1,576.0 | ) |  | (1.0 | ) |  | (2,099.5 | )
Payments/returns relating to sales in prior years | (53.2 | ) |  | (536.0 | ) |  | (19.8 | ) |  | (609.0 | )
Ending balance | $ | 71.6 |  |  | $ | 482.7 |  |  | $ | 51.2 |  |  | $ | 605.5 |
(In millions) | Discounts |  | Contractual Adjustments |  | Returns |  | Total
2015 |  |  |  |  |  |  |
Beginning balance | $ | 47.6 |  |  | $ | 387.1 |  |  | $ | 49.1 |  |  | $ | 483.8 |
Current provisions relating to sales in current year | 459.7 |  |  | 1,732.1 |  |  | 37.6 |  |  | 2,229.4 |
Adjustments relating to prior years | (1.3 | ) |  | (16.3 | ) |  | (14.7 | ) |  | (32.3 | )
Payments/returns relating to sales in current year | (405.9 | ) |  | (1,258.1 | ) |  | (2.6 | ) |  | (1,666.6 | )
Payments/returns relating to sales in prior years | (44.0 | ) |  | (296.1 | ) |  | (11.5 | ) |  | (351.6 | )
Ending balance | $ | 56.1 |  |  | $ | 548.7 |  |  | $ | 57.9 |  |  | $ | 662.7 |
(In millions) | Discounts |  | Contractual Adjustments |  | Returns |  | Total
2014 |  |  |  |  |  |  |
Beginning balance | $ | 47.0 |  |  | $ | 345.5 |  |  | $ | 33.7 |  |  | $ | 426.2 |
Current provisions relating to sales in current year | 347.3 |  |  | 1,265.4 |  |  | 39.1 |  |  | 1,651.8 |
Adjustments relating to prior years | (1.0 | ) |  | (28.5 | ) |  | 13.5 |  |  | (16.0 | )
Payments/returns relating to sales in current year | (299.7 | ) |  | (933.4 | ) |  | (4.1 | ) |  | (1,237.2 | )
Payments/returns relating to sales in prior years | (46.0 | ) |  | (261.9 | ) |  | (33.1 | ) |  | (341.0 | )
Ending balance | $ | 47.6 |  |  | $ | 387.1 |  |  | $ | 49.1 |  |  | $ | 483.8 |
Total reserves, included in consolidated balance sheets |
| As of December 31,
(In millions) | 2016 |  | 2015
Reduction of accounts receivable | $ | 166.9 |  |  | $ | 144.6 |
Component of accrued expenses and other | 438.6 |  |  | 518.1 |
Total revenue-related reserves | $ | 605.5 |  |  | $ | 662.7 |

X
- Definition Analysis of amount of and change in product revenue reserves. + References No definition available. + Details
Name: | biib_AnalysisOfAmountOfAndChangeInProductRevenueReservesTableTextBlock
Namespace Prefix: | biib_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Revenue reserves. + References No definition available. + Details
Name: | biib_ReservesForDiscountsAndAllowancesAbstract
Namespace Prefix: | biib_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Summary of total product revenue reserves included in consolidated balance sheets. + References No definition available. + Details
Name: | biib_SummaryOfProductRevenueReservesIncludedInConsolidatedBalanceSheetsTableTextBlock
Namespace Prefix: | biib_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration