Shareholders' Equity (Details - Share Repurchases) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jul. 31, 2019	Oct. 31, 2018
Repurchases of common stock	$ 1,085	$ 1,140	$ 362
Common Stock
Repurchases of common stock, shares	24,800,000	22,000,000	9,000,000
Repurchases of common stock	$ 1,100	$ 1
Average repurchase price	$ 43.81
Debt Conversion, Original Debt, Amount			$ 3
Debt Conversion, Converted Instrument, Shares Issued	0	0	300,000
Common Stock | Current share repurchase program [Member]
Repurchases of stock, authorized amount				$ 1,500
Repurchases of common stock, shares	14,000,000.0
Repurchases of common stock	$ 586
Average repurchase price	$ 41.97
Common Stock | Prior share repurchase program [Member]
Repurchases of stock, authorized amount					$ 1,000
Repurchases of common stock, shares	10,800,000
Repurchases of common stock	$ 499
Average repurchase price	$ 46.18