Income Taxes - Undistributed Earnings and Foreign Location Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes.
Income tax benefits attributable to reduced tax rates or exemptions in foreign locations	$ 163	$ 127	$ 227
EPS impact of reduced tax rates or exemptions in foreign locations (in dollars per diluted share)	$ 0.28	$ 0.22	$ 0.38

The amount of income taxes from which a reporting entity is exempt or for which it will receive a reduction in income taxes as a result of the income tax holiday granted by the taxing jurisdiction.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=116825942&loc=d3e330215-122817

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration