Stockholders' Equity (Narrative) (Details) - USD ($) shares in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2019	Jan. 30, 2019
Class of Stock [Line Items]
Shares repurchased	$ 771,000,000	$ 1,991,000,000
Common Stock [Member]
Class of Stock [Line Items]
Share repurchase, authorized amount			$ 4,000,000,000.0
Shares repurchased (in shares)	20	49
Shares repurchased	$ 771,000,000	$ 2,000,000,000.0

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-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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