Stock Based Awards and Other Equity Instruments - Summary of RSU Activity For MSUs (Details) - MSUs - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018
MSUs outstanding
Unvested outstanding, Beginning balance	284		213	[1]
Unvested MSUs, Granted	121	[2],[3]	71	[4]
Unvested MSUs, Cancelled	(16)
Unvested outstanding, Ending balance	389		284
Weighted Average Grant-Date Fair Value Per Share
Unvested outstanding, Weighted Average Grant-Date Fair Value Per Share, Beginning balance	$ 37.41		$ 30.04	[1]
Weighted Average Grant-Date Fair Value Per Share, Granted	51.76	[2],[3]	59.40	[4]
Weighted Average Grant-Date Fair Value Per Share, Cancelled	58.63
Unvested outstanding, Weighted Average Grant-Date Fair Value Per Share, Ending balance	$ 40.99		$ 37.41
Aggregate Intrinsic Value
Unvested MSUs outstanding, Aggregate Intrinsic Value	$ 12

[1] Represents 213,000 market-based RSU or MSUs awarded to the Company’s CEO in November 2017. The MSU award provides for vesting based upon the Company’s total shareholder return, or TSR, performance over the period commencing January 1, 2018 through December 31, 2020 relative to the TSR performance of the Nasdaq Composite Total Return Index. Based upon actual attainment relative to the target performance metric, the CEO has the ability to receive up to 125% of the target number of MSUs originally granted, or to be issued none at all.

[2] Inclusive of 42,477 dividend equivalents issued to employees holding non-vested MSU grant awards in conjunction with our special cash dividend declared on November 1, 2019, which will be payable to the holder subject to, and upon vesting of, the underlying awards.

[3] Inclusive of 78,050 MSUs which provide for vesting based upon the Company’s total shareholder return, or TSR, performance over the period commencing January 1, 2019 through December 31, 2021 relative to the TSR performance of the Nasdaq Composite Total Return Index. Based upon actual attainment relative to the target performance metric, the grantee has the ability to receive up to 200% of the target number of MSUs originally granted, or to be issued none at all. These MSUs were granted under the 2018 Plan.

[4] MSUs provide for vesting based upon the Company’s total shareholder return, or TSR, performance over the period commencing January 1, 2018 through December 31, 2020 relative to the TSR performance of the Nasdaq Composite Total Return Index. Based upon actual attainment relative to the target performance metric, the grantee has the ability to receive up to 200% of the target number of MSUs originally granted, or to be issued none at all. These MSUs were granted under the 2011 Plan.