Shareholders' Equity - Dividends Declared (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
Nov. 30, 2020	Aug. 31, 2020	May 31, 2020	Feb. 29, 2020	Nov. 30, 2019	Aug. 31, 2019	May 31, 2019	Feb. 28, 2019
Equity [Abstract]
Dividends declared per share (USD per share)	$ 0	$ 0	$ 0	$ 0.50	$ 0.50	$ 0.50	$ 0.50	$ 0.50
Dividends declared	$ 0	$ 0	$ 0	$ 342	$ 346	$ 342	$ 346	$ 345

Amount of paid and unpaid common stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 405
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6957935&loc=d3e64057-112817

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration