Shareholders' Equity (Details) - USD ($)	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Nov. 02, 2016
Equity, Class of Treasury Stock [Line Items]
Stock repurchased during period (in shares)	0	0
Dividends declared per share (in dollars per share)	$ 0.50	$ 0.50
2016 Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, authorized amount			$ 15,000,000,000.0
Stock repurchase program, remaining authorized repurchase amount	$ 13,900,000,000

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration