Stockholders' Equity - Stock Repurchases (Details) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021 USD ($) shares	Jun. 30, 2021 USD ($) shares
Equity [Abstract]
Common stock authorized to be repurchased	$ 5,000	$ 5,000
Stock repurchased (in shares) \| shares	1,001,565	1,001,565
Repurchases of common stock to be held as treasury stock	$ 500	$ 500
Remaining authorized repurchase amount	$ 4,500	$ 4,500

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
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Balance Type:	debit
Period Type:	duration