The increase (decrease) during the reporting period in the account that represents the temporary difference that results from Income or Loss that is recognized for accounting purposes but not for tax purposes and vice versa.

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Amount of significant reductions in the period of other assets (current, noncurrent, or unclassified).

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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

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Nature of Operations and Significant Accounting Policies - Recent Accounting Pronouncements (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Recent Accounting Pronouncements
Stockholders' Equity	$ 12,921.9	$ 16,617.3	$ 14,685.8	$ 11,456.0
Accumulated other comprehensive income (loss)
Recent Accounting Pronouncements
Stockholders' Equity	165.5	2,383.1	1,037.9	(1,565.1)
Retained earnings (accumulated deficit)
Recent Accounting Pronouncements
Stockholders' Equity	9,482.9	$ 11,838.0	11,074.3	10,290.2
ASU 2018-02 - Reclassification of certain tax effects \| Accumulated other comprehensive income (loss) \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	77.6
ASU 2018-02 - Reclassification of certain tax effects \| Retained earnings (accumulated deficit) \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	(77.6)
ASU 2014-09 - Revenue recognition \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	(39.7)
ASU 2014-09 - Revenue recognition \| Accumulated other comprehensive income (loss) \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	25.6
ASU 2014-09 - Revenue recognition \| Retained earnings (accumulated deficit) \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	(65.0)
ASU 2016-16 - Intra-entity asset transfer taxes \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	8.7
Cumulative effect adjustment, decrease to other assets	21.1
Cumulative effect adjustment, decrease to deferred income taxes	29.8
ASU 2016-16 - Intra-entity asset transfer taxes \| Retained earnings (accumulated deficit) \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	8.7
ASU 2016-01 - Equity investments \| Accumulated other comprehensive income (loss) \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	(1.0)
ASU 2016-01 - Equity investments \| Retained earnings (accumulated deficit) \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity	$ 1.0
ASU 2016-02 - Leases \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity				4.0
ASU 2016-02 - Leases \| Retained earnings (accumulated deficit) \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity				$ 4.0
ASU 2016-13 - CECL \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity			(8.4)
ASU 2016-13 - CECL \| Retained earnings (accumulated deficit) \| Effects of implementation of accounting change
Recent Accounting Pronouncements
Stockholders' Equity			$ (8.4)